CHAPTER 41
WATER SUPPLIES
[These rules transferred from Health Department, 1971 IDR (Title II, Chs 1 and 2)]
[Prior to 7/1/83, DEQ Ch 22]
[Prior to 12/3/86, Water, Air and Waste Management[900]]
567—41.1(455B) Primary drinking water regulations—coverage. 567—Chapters 40 through 44 and 83 shall apply to each public water supply system, unless the public water supply system meets all of the following conditions:
	1.	Consists only of distribution and storage facilities (and does not have any collection and treatment facilities);
	2.	Obtains all of its water from, but is not owned or operated by, a public water supply system to which such regulations apply;
	3.	Does not sell water to any person; and
	4.	Is not a carrier which conveys passengers in interstate commerce.
567—41.2(455B) Biological maximum contaminant level (MCL), treatment technique (TT), and monitoring requirements.
	41.2(1) Coliform bacteria and E. coli. The provisions of this subrule include both maximum contaminant level and treatment technique requirements. The provisions of this subrule apply to all public water systems. Failure to comply with the applicable requirements in this subrule is a violation of the national primary drinking water regulations.
	a. 	Maximum contaminant level. A public water system must determine compliance with the MCL for E. coli for each month in which the system is required to monitor for total coliforms. A system is in compliance with the MCL for E. coli for samples taken under this subrule unless any of the following conditions occur. For purposes of the public notification requirements in 567—42.1(455B), violation of the MCL may pose an acute risk to health.
	(1)	E. coli-positive repeat sample. The system has an E. coli-positive repeat sample following a total coliform-positive routine sample.
	(2)	E. coli-positive routine sample. The system has a total coliform-positive repeat sample following an E. coli-positive routine sample.
	(3)	Failure to collect all required repeat samples following E. coli-positive routine samples. The system fails to take all required repeat samples following an E. coli-positive routine sample.
	(4)	Failure to test for E. coli on any total coliform-positive repeat sample. The system fails to test for E. coli when any repeat sample tests positive for total coliform.
	b. 	Analytical methodology.
	(1)	Sample volume. The standard sample volume required for analysis is 100 mL, regardless of the analytical method used.
	(2)	Presence/absence required. Only the presence or absence of total coliforms and E. coli is required to be determined in any compliance sample; a determination of density is acceptable but is not required.
	(3)	Holding time and temperature. The time from sample collection to initiation of test medium incubation may not exceed 30 hours. Systems are encouraged but not required to hold samples below 10° C during transit.
	(4)	Dechlorinating agent required for chlorinated water. If water having a residual chlorine (measured as free, combined, or total chlorine) is to be analyzed, sufficient sodium thiosulfate (Na2S2O3) must be added to the sample bottle before sterilization to neutralize any residual chlorine in the water sample. Dechlorination procedures are addressed in Section 9060A.2 of Standard Methods for the Examination of Water and Wastewater (20th and 21st editions).
	(5)	Systems must conduct total coliform and E. coli analyses in accordance with one of the analytical methods in the following table.

Methodology Category	Method1	Citation1	
Total Coliform Bacteria Methods:	
Lactose Fermentation Methods	Standard Total Coliform Fermentation Technique	Standard Methods 9221 B.1, B.2 (20th, 21st, and 22nd ed.)2, 3
Standard Methods Online 9221 B.1, B.2-99, B-062, 3	
	Presence-Absence (P-A) Coliform Test	Standard Methods 9221 D.1, D.2 (20th and 21st ed.)2, 7
Standard Methods Online 9221 D.1, D.2-992, 7	
Membrane Filtration Methods	Standard Total Coliform Membrane Filter Procedure	Standard Methods 9222 B, C (20th and 21st ed.)2, 4
Standard Methods Online 9222 B-972, 4, 9222 C-972, 4	
	Membrane Filtration using MI Medium	EPA Method 16042	
	m-ColiBlue24 Test2, 4	 	
	Chromocult2, 4	 	
Enzyme Substrate Methods	Colilert	Standard Methods 9223 B (20th, 21st and 22nd ed.)2, 5
Standard Methods Online 9223 B-97, B-042, 5	
	Colilert-18	Standard Methods 9223 B (21st and 22nd ed.)2, 5
Standard Methods Online 9223 B-042, 5	
	Colisure	Standard Methods 9223 B (20th, 21st and 22nd ed.)2, 5, 6
Standard Methods Online 9223 B-97, B-042, 5, 6	
	E*Colite Test2	 	
	Readycult Test2	 	
	modified Colitag Test2	 	
	Tecta EC/TC Test2	 	
Escherichia coli (E. coli) Methods:	
Escherichia coli Procedures (following Lactose Fermentation Methods)	EC-MUG Medium	Standard Methods 9221 F.1 (20th, 21st and 22nd ed.)2
Standard Methods Online 9221 F-062	
Escherichia coli Partition Method	EC broth with MUG (EC-MUG)	Standard Methods 9222 G.1c(2) (20th and 21st ed.)2, 8	
	NA-MUG Medium	Standard Methods 9222 G.1c(1) (20th and 21st ed.)2	
Membrane Filtration Methods	Membrane Filtration using MI Medium	EPA Method 16042	
	m-ColiBlue24 Test2, 4	 	
	Chromocult2, 4	 	
Enzyme Substrate Methods	Colilert	Standard Methods 9223 B (20th, 21st and 22nd ed.)2, 5
Standard Methods Online 9223 B-97, B-042, 5, 6	
	Colilert-18	Standard Methods 9223 B (21st and 22nd ed.)2, 5
Standard Methods Online 9223 B-042, 5	
	Colisure	Standard Methods 9223 B (20th, 21st and 22nd ed.)2, 5, 6
Standard Methods Online 9223 B-97, 042, 5, 6	
	E*Colite Test2	 	
	Readycult Test2	 	
	modified Colitag Test2	 	
	Tecta EC/TC Test2	 	
1The procedures must be done in accordance with the documents listed in 41.2(1)“a”(6). For Standard Methods, either the 20th (1998) or 21st (2005) edition may be used. For Standard Methods Online, the year in which each method was approved by the Standard Methods Committee is designated by the last two digits following the hyphen in the method number. The methods listed are the only online versions that may be used. For vendor methods, the date of the method listed in 41.2(1)“a”(6) is the date/version of the approved method. The methods listed are the only versions that may be used for compliance with this rule. Laboratories should be careful to use only the approved versions of the methods, as product package inserts may not be the same as the approved versions of the methods.
2Incorporated by reference. See 41.2(1)“a”(6).
3Lactose broth, as commercially available, may be used in lieu of lauryl tryptose broth if the system conducts at least 25 parallel tests between lactose broth and lauryl tryptose broth using the water normally tested and if the findings from this comparison demonstrate that the false-positive rate and the false-negative rate for total coliforms, using lactose broth, is less than 10 percent.
4All filtration series must begin with membrane filtration equipment that has been sterilized by autoclaving. Exposure of filtration equipment to UV light is not adequate to ensure sterilization. Subsequent to the initial autoclaving, exposure of the filtration equipment to UV light may be used to sanitize the funnels between filtrations within a filtration series. Alternatively, membrane filtration equipment that is presterilized by the manufacturer (i.e., disposable funnel units) may be used.
5Multiple-tube and multi-well enumerative formats for this method are approved for use in presence-absence determination under this subrule.
6Colisure results may be read after an incubation time of 24 hours.
7A multiple-tube enumerative format, as described in Standard Methods for the Examination of Water and Wastewater 9221, is approved for this method for use in presence-absence determination under this subrule.
8The following changes must be made to the EC broth with MUG (EC-MUG) formulation: Potassium dihydrogen phosphate, KH2PO4, must be 1.5 g, and 4-methylumbelliferyl-beta-D-glucuronide must be 0.05 g.
	(6)	Methods incorporated by reference. The standards required in this subrule are incorporated by reference with the approval of the Director of the Federal Register under 5 U.S.C. 552(a) and 1 CFR Part 51. All approved material is available for inspection either electronically at www.regulations.gov, in hard copy at the Water Docket, or from the sources indicated below. The Docket ID is EPA-HQ-OW-2008-0878. Hard copies of these documents may be viewed at the Water Docket in the EPA Docket Center, (EPA/DC) EPA West, Room 3334, 1301 Constitution Avenue, NW, Washington, DC. The EPA Docket Center Public Reading Room is open from 8:30 a.m.	to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202)566-1744, and the telephone number for the Water Docket is (202)566-2426. Copyrighted materials are only available for viewing in hard copy. These documents are also available for inspection at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202)741-6030 or go to www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
	1.	American Public Health Association, 800 I Street, NW, Washington, DC 20001. Standard Methods for the Examination of Water and Wastewater, 20th edition (1998):
	●	Standard Methods 9221, “Multiple-Tube Fermentation Technique for Members of the Coliform Group,” B.1, B.2, “Standard Total Coliform Fermentation Technique.”
	●	Standard Methods 9221, “Multiple-Tube Fermentation Technique for Members of the Coliform Group,” D.1, D.2, “Presence-Absence (P-A) Coliform Test.”
	●	Standard Methods 9222, “Membrane Filter Technique for Members of the Coliform Group,” B, “Standard Total Coliform Membrane Filter Procedure.”
	●	Standard Methods 9222, “Membrane Filter Technique for Members of the Coliform Group,” C, “Delayed-Incubation Total Coliform Procedure.”
	●	Standard Methods 9223, “Enzyme Substrate Coliform Test,” B, “Enzyme Substrate Test,” Colilert and Colisure.
	●	Standard Methods 9221, “Multiple-Tube Fermentation Technique for Members of the Coliform Group,” F.1, “Escherichia coli Procedure: EC-MUG Medium.”
	●	Standard Methods 9222, “Membrane Filter Technique for Members of the Coliform Group,” G.1c(2), “Escherichia coli Partition Method: EC Broth with MUG (EC-MUG).”
	●	Standard Methods 9222, “Membrane Filter Technique for Members of the Coliform Group,” G.1c(1), “Escherichia coli Partition Method: NA-MUG Medium.”
	2.	American Public Health Association, 800 I Street, NW, Washington, DC 20001. Standard Methods for the Examination of Water and Wastewater, 21st edition (2005):
	●	Standard Methods 9221, “Multiple-Tube Fermentation Technique for Members of the Coliform Group,” B.1, B.2, “Standard Total Coliform Fermentation Technique.”
	●	Standard Methods 9221, “Multiple-Tube Fermentation Technique for Members of the Coliform Group,” D.1, D.2, “Presence-Absence (P-A) Coliform Test.”
	●	Standard Methods 9221, “Membrane Filter Technique for Members of the Coliform Group,” B, “Standard Total Coliform Membrane Filter Procedure.”
	●	Standard Methods 9222, “Membrane Filter Technique for Members of the Coliform Group,” C, “Delayed-Incubation Total Coliform Procedure.”
	●	Standard Methods 9223, “Enzyme Substrate Coliform Test,” B, “Enzyme Substrate Test,” Colilert and Colisure.
	●	Standard Methods 9221, “Multiple-Tube Fermentation Technique for Members of the Coliform Group,” F.1, “Escherichia coli Procedure: EC-MUG Medium.”
	●	Standard Methods 9222, “Membrane Filter Technique for Members of the Coliform Group,” G.1.c(2), “Escherichia coli Partition Method: EC Broth with MUG (EC-MUG).”
	●	Standard Methods 9222, “Membrane Filter Technique for Members of the Coliform Group,” G.1.c(1), “Escherichia coli Partition Method: NA-MUG Medium.”
	3.	American Public Health Association, 800 I Street, NW, Washington, DC 20001. “Standard Methods Online” available at www.standardmethods.org:
	●	Standard Methods Online 9221, “Multiple-Tube Fermentation Technique for Members of the Coliform Group” (1999), B.1, B.2-99, B-06, “Standard Total Coliform Fermentation Technique.”
	●	Standard Methods Online 9221, “Multiple-Tube Fermentation Technique for Members of the Coliform Group” (1999), D.1, D.2-99, “Presence-Absence (P-A) Coliform Test.”
	●	Standard Methods Online 9222, “Membrane Filter Technique for Members of the Coliform Group” (1997), B-97, “Standard Total Coliform Membrane Filter Procedure.”
	●	Standard Methods Online 9222, “Membrane Filter Technique for Members of the Coliform Group” (1997), C-97, “Delayed-Incubation Total Coliform Procedure.”
	●	Standard Methods Online 9223, “Enzyme Substrate Coliform Test” (1997), B-97, “Enzyme Substrate Test,” Colilert and Colisure.
	4.	Charm Sciences, Inc., 659 Andover Street, Lawrence, MA 01843-1032; telephone (800)343-2170: E*Colite—“Charm E*Colite Presence/Absence Test for Detection and Identification of Coliform Bacteria and Escherichia coli in Drinking Water,” January 9, 1998.
	5.	CPI International, Inc., 5580 Skylane Blvd., Santa Rosa, CA 95403; telephone (800)878-7654: modified Colitag, ATP D05-0035—“Modified Colitag Test Method for the Simultaneous Detection of E. coli and other Total Coliforms in Water,” August 28, 2009.
	6.	EMD Millipore (a division of Merck KGaA, Darmstadt, Germany), 290 Concord Road, Billerica, MA 01821; telephone (800)645-5476:
	●	Chromocult—“Chromocult Coliform Agar Presence/Absence Membrane Filter Test Method for Detection and Identification of Coliform Bacteria and Escherichia coli for Finished Waters,” November 2000, Version 1.0.
	●	Readycult—“Readycult Coliforms 100 Presence/Absence Test for Detection and Identification of Coliform Bacteria and Escherichia coli in Finished Waters,” January 2007, Version 1.1.
	7.	EPA’s Water Resource Center (MC-4100T), 1200 Pennsylvania Avenue, NW, Washington, DC 20460; telephone (202)566-1729: EPA Method 1604, EPA 821-R-02-024—“EPA Method 1604: Total Coliforms and Escherichia coli in Water by Membrane Filtration Using a Simultaneous Detection Technique (MI Medium),” September 2002, www.nemi.gov.
	8.	Hach Company, P.O. Box 389, Loveland, CO 80539; telephone (800)604-3493: m-ColiBlue24—“Membrane Filtration Method m-ColiBlue24 Broth,” Revision 2, August 17, 1999.
	9.	American Public Health Association, 800 I Street, NW, Washington, DC 20001. Standard Methods for the Examination of Water and Wastewater, 22nd edition (2012):
	●	Standard Methods 9221, “Multiple-Tube Fermentation Technique for Members of the Coliform Group,” B.1, B.2, “Standard Total Coliform Fermentation Technique.”
	●	Standard Methods 9223, “Enzyme Substrate Coliform Test,” B, “Enzyme Substrate Test,” Colilert and Colisure.
	●	Standard Methods 9221, “Multiple-Tube Fermentation Technique for Members of the Coliform Group,” F.1, “Escherichia coli Procedure: EC-MUG Medium.”
	10.	Veolia Water Solutions and Technologies, Suite 4697, Biosciences Complex, 116 Barrie Street, Kingston, Ontario, Canada K7L 3N6: Tecta EC/TC. “Presence/Absence Method for Simultaneous Detection of Total Coliforms and Escherichia coli in Drinking Water,” April 2014.
	(7)	Laboratory certification. Systems must have all compliance samples required under this subrule analyzed by a laboratory certified by the department in accordance with 567—Chapter 83 to analyze drinking water samples. The laboratory used by the system must be certified for each method and associated contaminant used for compliance monitoring analyses under this subrule.
	c. 	Sampling plan.
	(1)	Written sampling plan required. Systems must collect total coliform samples according to the written sampling plan.
	1.	Systems must develop a written sampling plan that identifies sample locations and a sample collection schedule that are representative of water throughout the distribution system. Major elements of the plan shall include, but not be limited to, the following:
	●	Map of the distribution system served by the system;
	●	List of routine compliance sample locations for each sample period;
	●	List of repeat compliance sample locations for each routine compliance sample location;
	●	Any other sample locations necessary to meet the requirements of this subrule;
	●	Sample collection schedule;
	●	Proper sampling technique instructions;
	●	Log of samples taken; and
	●	For groundwater systems subject to 567—41.7(455B), triggered source water monitoring plan.
	2.	The system shall review the sampling plan every two years and update it as needed and shall retain the sampling plan on file at the facility. The plan must be made available to the department upon request and for review during sanitary surveys and must be revised by the system at the direction of the department.
	3.	Monitoring under this subrule may take place at a customer’s premises, dedicated sampling station, or other designated compliance sampling location.
	(2)	Sampling schedule. Systems must collect routine samples at regular time intervals throughout the month. Systems that use only groundwater and serve 4,900 or fewer people, or regional water systems that use only groundwater and serve less than 121 miles of pipe, may collect all required routine samples on a single day if the samples are taken from different sites.
	(3)	Minimum number of required routine samples. Systems must take at least the minimum number of required routine samples even if the system has had an E. coli MCL violation or has exceeded the coliform treatment technique triggers in 41.2(1)“l.” Such samples must be designated as “routine” when submitted to the laboratory.
	(4)	Additional compliance monitoring samples. A system may conduct more compliance monitoring than is required to investigate potential problems in the distribution system and may use monitoring as a tool to assist in uncovering problems. A system may take more than the minimum number of required routine samples and must include the results when calculating whether the coliform treatment technique trigger in 41.2(1)“l”(1)“1” and “2” has been exceeded only if the samples are taken in accordance with the existing sampling plan and are representative of water throughout the distribution system. Such samples must be designated as “routine” when submitted to the laboratory.
	(5)	Repeat samples. Systems must identify repeat monitoring locations in the sampling plan. Repeat samples must be analyzed at the same laboratory as the corresponding original routine sample(s), unless written approval for use of a different laboratory is granted by the department. The system must collect at least one repeat sample from the sampling tap where the original routine total coliform-positive sample was taken, at least one repeat sample at a tap within five service connections upstream of the original sample location, and at least one repeat sample at a tap within five service connections downstream of the original sample location. Such samples must be designated as “repeat” when submitted to the laboratory.
	1.	If the sampling location of a total coliform-positive sample is at or within one service connection from the end of the distribution system, the system must still take all required repeat samples. However, the department may allow an alternative sampling location in lieu of one of the upstream or downstream sampling locations.
	2.	A groundwater system with two or more wells that is required to conduct triggered source water monitoring under subrule 41.7(3) must collect groundwater source sample(s) in addition to the required repeat samples.
	3.	A groundwater system with a single well that is required to conduct triggered source water monitoring may, with written department approval, collect one of its required repeat samples at the triggered source water sample monitoring location. The system must demonstrate to the department’s satisfaction that the sampling plan remains representative of water quality in the distribution system. If approved, the sample result may be used to meet the requirements of subrule 41.7(3) and this subrule. If a repeat sample taken at the triggered source water monitoring location is E. coli-positive, the system has violated the E. coli MCL, and must also comply with the requirements for additional source water samples under 41.7(3)“a”(3).
	4.	The department may review, revise, and approve, as appropriate, repeat sampling proposed by the system under 41.2(1)“c”(5). The system must demonstrate that the sampling plan remains representative of the water quality in the distribution system.
	(6)	Special purpose samples. Special purpose samples, such as those taken to determine whether disinfection practices are sufficient following pipe placement, replacement, or repair, must not be used to determine whether the coliform treatment technique trigger has been exceeded. Repeat samples are not considered special purpose samples and must be used to determine whether the coliform treatment technique trigger has been exceeded. Such samples must be designated as “special” when submitted to the laboratory and cannot be used for compliance.
	(7)	Residual disinfectant measurement. Any system adding a chemical disinfectant to the water must meet the requirements specified in 567—subparagraph 42.4(3)“b”(1). The minimum required residual disinfectant measurements are as follows, unless otherwise directed by the department in writing:
	1.	Groundwater systems. A system that uses only groundwater and adds a chemical disinfectant or provides water that contains a disinfectant must measure and record the free and total chlorine residual disinfectant concentration at least at the same points in the distribution system and at the same time as routine and repeat total coliform bacteria samples are collected, as specified in 41.2(1)“e” through 41.2(1)“j.” The system shall report the residual disinfectant concentration to the laboratory with the bacteria sample and comply with the applicable reporting requirements of 567—subrule 42.4(3).
	2.	Surface water and influenced groundwater systems.
	●	Any surface water or IGW PWS must meet the requirements for minimum residual disinfectant entering the distribution system pursuant to 567—paragraph 43.5(4)“b”(2)“1”; and
	●	A system that uses surface water or IGW must comply with the requirements specified in 567—paragraph 43.5(4)“b”(2)“2” for daily distribution system residual disinfectant monitoring. The system must measure and record the free and total chlorine residual disinfectant concentration at least at the same points in the distribution system and at the same time as routine and repeat total coliform bacteria samples are collected, as specified in 41.2(1)“e” through 41.2(1)“j.” The residual disinfectant measurements required as a part of this subrule may be used to satisfy the requirement in 567—paragraph 43.5(4)“b”(2)“2” on the day(s) when a routine or repeat total coliform bacteria sample(s) is collected, in lieu of separate samples. The system shall report the residual disinfectant concentration to the laboratory with the bacteria sample and comply with the applicable reporting requirements of 567—subrule 42.4(3).
	d. 	Invalidation of total coliform samples. A total coliform-positive sample invalidated under this paragraph does not count toward meeting the minimum monitoring requirements of this subrule.
	(1)	The department may invalidate a total coliform-positive sample only if the following conditions are met:
	1.	The laboratory establishes that improper sample analysis caused the total coliform-positive result.
	2.	The department, on the basis of the results of the required repeat samples, determines that the total coliform-positive sample resulted from a domestic or other non-distribution system plumbing problem. “Domestic or other non-distribution system plumbing problem” means a coliform contamination problem in a public water system with more than one service connection that is limited to the specific service connection from which the coliform-positive sample was taken. The department cannot invalidate a sample on the basis of repeat sample results unless all repeat samples collected at the same tap as the original total coliform-positive sample are also total coliform-positive and all repeat samples collected at a location other than the original tap are total coliform-negative. The department cannot invalidate a total coliform-positive sample on the basis of repeat samples if all the repeat samples are total coliform-negative or if the system has only one service connection.
	3.	The department has substantial grounds to believe that the total coliform-positive result is due to a circumstance or condition that does not reflect water quality in the distribution system. The system must still collect all repeat samples required under 41.2(1)“j” and use them to determine whether a coliform treatment technique trigger in 41.2(1)“l” has been exceeded.
The decision and supporting rationale for invalidating a total coliform-positive sample under 41.2(1)“d”(1) must be documented in writing, and approved and signed by the supervisor of the water supply operations section or water supply engineering section and the department official who recommended the decision. The department must make this document available to EPA and the public. The written documentation must state the specific cause of the total coliform-positive sample and what action the system has taken, or will take, to correct this problem. The department may not invalidate a total coliform-positive sample solely on the grounds that all repeat samples are total coliform-negative or because of poor sampling technique.
	(2)	Laboratory invalidation. A laboratory must invalidate a total coliform sample (unless total coliforms are detected, in which case the sample is valid) if the sample produces a turbid culture in the absence of gas production using an analytical method where gas formation is examined (e.g., the multiple-tube fermentation technique), produces a turbid culture in the absence of an acid reaction in the presence-absence (P-A) coliform test, or exhibits confluent growth or produces colonies too numerous to count with an analytical method using a membrane filter (e.g., membrane filter technique). If a laboratory invalidates a sample because of such interference, the system must collect another sample from the same location as that of the original sample within 24 hours of being notified of the interference problem and must have the sample analyzed for the presence of total coliforms. The system must continue to resample within 24 hours and have the samples analyzed until a valid result is obtained. The department may waive the 24-hour time limit on a case-by-case basis.
	e. 	Routine monitoring for specific groundwater noncommunity water systems serving 1,000 or fewer people. This paragraph applies to noncommunity water systems using only groundwater (not IGW) as a source and serving 1,000 or fewer people. Groundwater noncommunity water systems that serve schools, preschools, and child care facilities, and all public water systems owned or managed by state agencies, such as parks and rest areas, must monitor at the same frequency as a like-sized community water system, in accordance with 41.2(1)“f,” 41.2(1)“g,” or 41.2(1)“h.”
	(1)	General. Following any total coliform-positive sample taken under 41.2(1)“e,” systems must comply with the repeat monitoring requirements and E. coli analytical requirements in 41.2(1)“j.” Once all monitoring required by 41.2(1)“e” and 41.2(1)“j” for a calendar month has been completed, systems must determine whether any coliform treatment technique triggers specified in 41.2(1)“l” have been exceeded. If any trigger has been exceeded, systems must complete assessments as required by 41.2(1)“l.”
	(2)	Monitoring frequency for total coliforms. Systems must monitor each calendar quarter that the system provides water to the public, with the following exceptions:
	1.	A system on quarterly monitoring that experiences any of the following events must begin monthly monitoring in the month following the event. The system must continue on monthly monitoring until the system meets the requirements for returning to quarterly monitoring.
	●	The system has an E. coli MCL violation.
	●	The system triggers one Level 2 assessment under the provisions of 41.2(1)“l” in a rolling 12-month period.
	●	The system triggers two Level 1 assessments under the provisions of 41.2(1)“l” in a rolling 12-month period.
	●	The system has a coliform treatment technique violation.
	●	The system has two coliform monitoring violations in a rolling 12-month period.
	●	The system has one monitoring coliform violation and one Level 1 assessment under the provisions of 41.2(1)“l” in a rolling 12-month period.
	2.	A system on monthly monitoring for reasons other than those identified in 41.2(1)“e”(2)“1” is not considered to be on increased monitoring for the purposes of 41.2(1).
	3.	Seasonal systems must sample each month in which they are in operation. All seasonal systems must also demonstrate completion of a department-approved start-up procedure before serving water to the public, which includes a requirement for a coliform-negative start-up sample.
	(3)	Evaluation of sampling frequency during a sanitary survey. During each sanitary survey, the department must evaluate the status of the system including the distribution system, to determine whether the system is on an appropriate monitoring schedule. The department may modify the system’s monitoring schedule, as necessary, or may allow the system to stay on its existing monitoring schedule, consistent with the provisions of 41.2(1)“e.”
	(4)	Requirements for returning from monthly to quarterly sampling frequency for nonseasonal noncommunity systems. The department may reduce the monitoring frequency for a nonseasonal noncommunity system on monthly monitoring triggered under 41.2(1)“e”(2)“1” to quarterly monitoring if the system meets the following criteria. For the purposes of 41.2(1)“e”(4), “protected water source” means the well meets separation distances from sources of microbial contamination pursuant to 567—subrule 43.3(7), Table A; or the system has 4-log virus inactivation treatment that is approved by the department and is in continuous usage.
	1.	Within the previous 12 months, the system must have a completed sanitary survey or voluntary Level 2 assessment, be free of sanitary defects, and have a protected water source;
	2.	The system must have a clean compliance history for a minimum of the previous 12 months; and
	3.	The department must review the approved sampling plan, which must designate the time period(s) for monitoring based on site-specific considerations (e.g., during periods of highest demand or highest vulnerability to contamination). The system must collect compliance samples during these time periods.
	(5)	Additional routine monitoring for systems on quarterly sampling in the month following a total coliform-positive routine sample. Systems collecting samples on a quarterly frequency must conduct additional routine monitoring the month following one or more total coliform-positive samples (with or without a Level 1 treatment technique trigger). Systems must collect at least three routine samples during the next month. Systems may either collect samples at regular time intervals throughout the month or may collect all required routine samples on a single day if samples are taken from different sites. Systems must use the results of additional routine samples in coliform treatment technique trigger calculations under 41.2(1)“l.”
	f. 	Routine monitoring for groundwater community water systems serving 1,000 or fewer people. This paragraph applies to community water systems using only groundwater (not IGW) as a source and serving 1,000 or fewer people.
	(1)	General. Following any total coliform-positive sample taken under 41.2(1)“f,” systems must comply with the repeat monitoring requirements and E. coli analytical requirements in 41.2(1)“j.” Once all monitoring required by 41.2(1)“f” and 41.2(1)“j” for a calendar month has been completed, systems must determine whether any coliform treatment technique triggers specified in 41.2(1)“l” have been exceeded. If any trigger has been exceeded, systems must complete assessments as required by 41.2(1)“l.”
	(2)	Monitoring frequency for total coliforms. The routine monitoring frequency for total coliforms is one sample per month.
	g. 	Routine monitoring requirements for SW/IGW public water systems serving 1,000 or fewer people. This paragraph applies to all public water supply systems serving 1,000 or fewer people that use surface water/influenced groundwater sources, including consecutive systems.
	(1)	General. Following any total coliform-positive sample taken under 41.2(1)“g,” systems must comply with the repeat monitoring requirements and E. coli analytical requirements in 41.2(1)“j.” Once all monitoring required by 41.2(1)“g” and 41.2(1)“j” for a calendar month has been completed, systems must determine whether any coliform treatment technique triggers specified in 41.2(1)“l” have been exceeded. If any trigger has been exceeded, systems must complete assessments as required by 41.2(1)“l.”
	(2)	Monitoring frequency for total coliforms. The routine monitoring frequency for total coliforms is one sample per month. Systems may not reduce monitoring frequency.
	(3)	Seasonal systems must sample each month in which they are in operation, and the monitoring frequency cannot be reduced. All seasonal systems must also demonstrate completion of a department-approved start-up procedure before serving water to the public, which includes a requirement for a coliform-negative start-up sample.
	h. 	Routine monitoring requirements for public water systems serving more than 1,000 people. The provisions of this paragraph apply to all public water systems serving more than 1,000 people except regional water systems. The requirements for regional water systems are listed in 41.2(1)“i.”
	(1)	General. Following any total coliform-positive sample taken under 41.2(1)“h,” systems must comply with the repeat monitoring requirements and E. coli analytical requirements in 41.2(1)“j.” Once all monitoring required by 41.2(1)“h” and 41.2(1)“l” for a calendar month has been completed, systems must determine whether any coliform treatment technique triggers specified in 41.2(1)“l” have been exceeded. If any trigger has been exceeded, systems must complete assessments as required by 41.2(1)“l.”
	(2)	Monitoring frequency for total coliforms. The routine monitoring frequency for total coliforms is based upon the population served by the system, as follows:

Population Served	Minimum Number of Routine Samples per Month	
1,001 to 2,500	2	
2,501 to 3,300	3	
3,301 to 4,100	4	
4,101 to 4,900	5	
4,901 to 5,800	6	
5,801 to 6,700	7	
6,701 to 7,600	8	
7,601 to 8,500	9	
8,501 to 12,900	10	
12,901 to 17,200	15	
17,201 to 21,500	20	
21,501 to 25,000	25	
25,001 to 33,000	30	
33,001 to 41,000	40	
41,001 to 50,000	50	
50,001 to 59,000	60	
59,001 to 70,000	70	
70,001 to 83,000	80	
83,001 to 96,000	90	
96,001 to 130,000	100	
130,001 to 220,000	120	
220,001 to 320,000	150	
320,001 to 450,000	180	
450,001 to 600,000	210	
600,001 to 780,000	240	
780,001 to 970,000	270	
970,001 to 1,230,000	300	
	(3)	Seasonal systems must sample each month in which they are in operation, and the monitoring frequency cannot be reduced. All seasonal systems must also demonstrate completion of a department-approved start-up procedure before serving water to the public, which includes a requirement for a coliform-negative start-up sample.
	(4)	Reduced monitoring. Community systems may not reduce the number of required routine samples.
	(5)	Increased monitoring. If the department, on the basis of a sanitary survey or monitoring results history, determines that some greater frequency of monitoring is more appropriate, that frequency shall be the frequency required under these rules. The increased frequency shall be confirmed or changed on the basis of subsequent surveys.
	i. 	Routine monitoring requirements for regional public water systems. The provisions of 41.2(1)“i” apply to all regional water systems. The supplier of water for a regional water system as defined in 567—40.2(455B) shall sample for coliform bacteria at a frequency based upon the miles of pipe in its distribution system.
	(1)	General. Following any total coliform-positive sample taken under 41.2(1)“i,” systems must comply with the repeat monitoring requirements and E. coli analytical requirements in 41.2(1)“j.” Once all monitoring required by 41.2(1)“i” and 41.2(1)“j” for a calendar month has been completed, systems must determine whether any coliform treatment technique triggers specified in 41.2(1)“l” have been exceeded. If any trigger has been exceeded, systems must complete assessments as required by 41.2(1)“l.”
	(2)	Monitoring frequency for total coliforms. The routine monitoring frequency for total coliforms is based upon the miles of pipe in the system’s distribution system, as indicated in the following chart. In no case shall the sampling frequency for a regional water system be less than as set forth in 41.2(1)“h” based upon the population equivalent served. The following chart represents sampling frequency per miles of pipe in the distribution system and is determined by calculating one-half the square root of the miles of pipe.

Miles of Pipe	Minimum Number of Routine Samples per Month	
0 – 9	1	
10 – 25	2	
26 – 49	3	
50 – 81	4	
82 – 121	5	
122 – 169	6	
170 – 225	7	
226 – 289	8	
290 – 361	9	
362 – 441	10	
442 – 529	11	
530 – 625	12	
626 – 729	13	
730 – 841	14	
842 – 961	15	
962 – 1,089	16	
1,090 – 1,225	17	
1,226 – 1,364	18	
1,365 – 1,521	19	
1,522 – 1,681	20	
1,682 – 1,849	21	
1,850 – 2,025	22	
2,026 – 2,209	23	
2,210 – 2,401	24	
2,402 – 2,601	25	
2,602 – 2,809	26	
2,810 – 3,025	27	
3,026 – 3,249	28	
3,250 – 3,481	29	
3,482 – 3,721	30	
3,722 – 3,969	31	
3,970 – 4,225	32	
4,226 – 4,489	33	
4,490 – 4,671	34	
4,672 – 5,041	35	
5,042 – 5,329	36	
5,330 – 5,625	37	
5,626 – 5,929	38	
5,930 – 6,241	39	
6,242 – 6,561	40	
6,562 and greater	41	
	(3)	Reduced monitoring. Regional water systems may not reduce the number of required routine samples.
	(4)	Increased monitoring. If the department, on the basis of a sanitary survey or monitoring results history, determines that some greater frequency of monitoring is more appropriate, that frequency shall be the frequency required under these rules. The increased frequency shall be confirmed or changed on the basis of subsequent surveys.
	j. 	Repeat monitoring. If a routine sample taken under 41.2(1)“e” through 41.2(1)“i” is total coliform-positive, the system must collect a set of repeat samples. The department cannot waive the requirement for a system to collect repeat samples.
	(1)	The system must collect no fewer than three repeat samples for each total coliform-positive routine sample found.
	(2)	The system must collect the repeat samples within 24 hours of being notified of the positive routine sample result. The department may extend the 24-hour limit on a case-by-case basis if the system has a logistical problem in collecting the repeat samples within 24 hours that is beyond its control. In the case of an extension, the department must specify how much time the system has to collect the repeat samples.
	(3)	The system must collect all repeat samples on the same day, except that the department may allow a system with a single service connection to collect the required set of repeat samples over a three-day period. “System with a single service connection” means a system which supplies drinking water to consumers through a single service line.
	(4)	The system must collect an additional set of repeat samples in the manner specified in 41.2(1)“j”(1) to (3) if one or more repeat samples in the current set of repeat samples is total coliform-positive. The system must collect the additional set of repeat samples within 24 hours of being notified of the positive result, unless the department extends the limit as provided in 41.2(1)“j”(2). The system must continue to collect additional sets of repeat samples until either total coliforms are not detected in one complete set of repeat samples or the system determines that a coliform treatment technique trigger specified in 41.2(1)“l” has been exceeded as a result of a total coliform-positive repeat sample and notifies the department. If a trigger identified in 41.2(1)“l” is exceeded as a result of a total coliform-positive routine sample, systems are required to conduct only one round of repeat monitoring for each total coliform-positive routine sample.
	(5)	Results of all routine and repeat samples taken under 41.2(1)“e” through 41.2(1)“i” that are not invalidated by the department must be used to determine whether a coliform treatment technique trigger specified in 41.2(1)“l” has been exceeded.
	k. 	E. coli testing requirements.
	(1)	If any routine or repeat sample is total coliform-positive, the system must analyze that total coliform-positive culture medium to determine the presence of E. coli. If E. coli are present, the system must notify the department by the end of the same day when the system is notified of the test result. If the notification is outside of the department’s routine office hours, the system shall call the department’s Environmental Emergency Reporting Hotline at (515)725-8694.
	(2)	The department has the discretion to allow a system, on a case-by-case basis, to forgo E. coli testing on a total coliform-positive sample if that system assumes that the total coliform-positive sample is E. coli-positive. Accordingly, the system must notify the department as specified in 41.2(1)“k”(1), and the provisions of 41.2(1)“a” apply.
	l. 	Coliform treatment technique triggers. Systems must conduct assessments in accordance with 41.2(1)“m” after exceeding any treatment technique trigger.
	(1)	Level 1 treatment technique triggers.
	1.	For systems taking 40 or more samples per month, the system exceeds 5.0 percent total coliform-positive samples for the month.
	2.	For systems taking fewer than 40 samples per month, the system has two or more total coliform-positive samples in the same month.
	3.	The system fails to take every required repeat sample after any single total coliform-positive sample.
	(2)	Level 2 treatment technique triggers.
	1.	An E. coli MCL violation, as specified in 41.2(1)“p”(1).
	2.	A second Level 1 trigger as defined in 41.2(1)“l”(1) within a rolling 12-month period, unless the department has determined a likely reason that the samples that caused the first Level 1 treatment technique trigger were total coliform-positive and has established that the system has corrected the problem.
	m. 	Assessment requirements. Systems must ensure that Level 1 and 2 assessments are conducted in order to identify the possible presence of sanitary defects and defects in distribution system coliform monitoring practices. Level 1 assessments may be conducted by the system owner or operator. Level 2 assessments must be conducted by the department with the assistance of the system owner or operator.
	(1)	General. When conducting assessments, systems must ensure that the assessor evaluates minimum elements that include review and identification of inadequacies in sample sites; sampling protocol; sample processing; atypical events that could affect distributed water quality or indicate that distributed water quality was impaired; changes in distribution system maintenance and operation that could affect distributed water quality (including water storage); source and treatment considerations that bear on distributed water quality, where appropriate (e.g., small groundwater systems); and existing water quality monitoring data. The system must conduct the assessment consistent with any department directives that tailor specific assessment elements with respect to the size and type of the system, and the size type, and characteristics of the distribution system.
	(2)	Level 1 assessment. A system must conduct a Level 1 assessment consistent with the department requirements if the system exceeds one of the treatment technique triggers in 41.2(1)“l”(1).
	1.	The system must complete the Level 1 assessment as soon as practical after any trigger in 41.2(1)“l”(1). In the completed assessment form, the system must describe sanitary defects detected, corrective actions completed, and a proposed timetable for any corrective actions not already completed. The system may also note on the assessment form that no sanitary defects were identified. The system must submit the completed Level 1 assessment form to the department within 30 days after the system learns that it has exceeded a trigger.
	2.	If the department reviews the completed Level 1 assessment and determines that the assessment is not sufficient (including any proposed timetable for any corrective actions not already completed), the department must consult with the system. If the department requires revisions after consultation, the system must submit a revised assessment form to the department on an agreed-upon schedule not to exceed 30 days from the date of the consultation.
	3.	Upon completion and submission of the assessment form by the system, the department must determine if the system has identified the likely cause for the Level 1 trigger and, if so, establish that the system has corrected the problem or has included a schedule acceptable to the department for correction of the problem.
	(3)	Level 2 assessment. A system must ensure that a Level 2 assessment is conducted if the system exceeds one of the treatment technique triggers in 41.2(1)“l”(2). The system must comply with any expedited actions or additional actions required by the department in the case of an E. coli MCL violation.
	1.	The system must ensure that a Level 2 assessment is completed by the department as soon as practical after any trigger in 41.2(1)“l”(2). The system must submit a completed Level 2 assessment form to the department within 30 days after the system learns that it has exceeded a trigger. The assessment form must contain a description of the sanitary defects detected, corrective actions completed, and a proposed timetable for any corrective actions not already completed. It may also be noted on the assessment form that no sanitary defects were identified.
	2.	If the department reviews the completed Level 2 assessment and determines that the assessment is not sufficient (including any proposed timetable for any corrective actions not already completed), the department must consult with the system. If the department requires revisions after consultation, the system must submit a revised assessment form to the department on an agreed-upon schedule not to exceed 30 days.
	3.	Upon completion and submission of the assessment form by the system, the department must determine if the system has identified the likely cause for the Level 2 trigger and determine whether the system has corrected the problem or has included a schedule acceptable to the department for correction of the problem.
	(4)	Corrective actions. A system must correct sanitary defects found through either a Level 1 or 2 assessment conducted under 41.2(1)“l.” For corrections not completed by the time of submission of the assessment form, the system must complete the corrective action(s) in compliance with a timetable approved by the department in consultation with the system. The system must notify the department when each scheduled corrective action is completed.
	(5)	Consultation. At any time during the assessment or corrective actions phase, either the water system or the department may request a consultation with the other party to determine the appropriate actions to be taken. The system may consult with the department on all relevant information that may impact on its ability to comply with a requirement of this subrule, including the method of accomplishment, an appropriate time frame, and other relevant information.
	n. 	Reporting requirements.
	(1)	E. coli.
	1.	The system must notify the department by the end of the same day when the system learns of an E. coli-positive violation. If the notification is outside of the department’s routine office hours, the system shall call the department’s Environmental Emergency Reporting Hotline at (515)725-8694.
	2.	The system must notify the department by the end of the same day when the system learns of the E. coli-positive routine sample. If the notification is outside of the department’s routine office hours, the system shall call the department’s Environmental Emergency Reporting Hotline at (515)725-8694.
	(2)	A system that has violated the treatment technique for coliforms in 41.2(1)“l” must report the violation to the department no later than the end of the next business day after it learns of the violation, and must notify the public in accordance with rule 567—42.1(455B).
	(3)	A system required to conduct an assessment under the provisions of 41.2(1)“l” must submit the assessment report within 30 days. The system must notify the department in accordance with 41.2(1)“m”(4) when each scheduled corrective action is completed for any corrections that were not completed by the time of submission of the assessment form.
	(4)	A system that has failed to comply with a coliform monitoring requirement must report the monitoring violation to the department within 10 days after the system discovers the violation, and must notify the public in accordance with rule 567—42.1(455B).
	(5)	A seasonal system must certify, prior to serving water to the public, that it has complied with the department-approved start-up procedure.
	o. 	Record-keeping requirements. Additional record-keeping requirements are listed in 567—paragraph 42.5(1)“j.”
	p. 	Violations.
	(1)	E. coli MCL violation. A system is in violation of the MCL for E. coli when any of the following occurs, and must conduct public notice in accordance with rule 567—42.1(455B):
	1.	The system has an E. coli-positive repeat sample following a total coliform-positive routine sample.
	2.	The system has a total coliform-positive repeat sample following an E. coli-positive routine sample.
	3.	The system fails to take all required repeat samples following an E. coli-positive routine sample.
	4.	The system fails to test for E. coli when any repeat sample tests positive for total coliform.
	(2)	Treatment technique violation. A system is in violation of a treatment technique trigger when any of the following occurs, and must conduct public notice in accordance with rule 567—42.1(455B):
	1.	A system exceeds a treatment technique trigger specified in 41.2(1)“l” and then fails to conduct the required assessment within the time frame specified in 41.2(1)“m.”
	2.	A system exceeds a treatment technique trigger specified in 41.2(1)“l” and then fails to conduct the required corrective actions within the time frame specified in 41.2(1)“m”(4).
	3.	A seasonal system fails to complete a department-approved start-up procedure prior to serving water to the public, including collection of a finished water sample that tests total coliform-negative.
	(3)	Monitoring violation. A system is in violation of monitoring requirements when any of the following occurs, and must conduct public notice in accordance with rule 567—42.1(455B):
	1.	Failure to take every required routine or additional routine sample in a compliance period.
	2.	Failure to analyze for E. coli following a total coliform-positive routine sample.
	(4)	Reporting violation. A system is in violation of reporting requirements when any of the following occurs, and must conduct public notice in accordance with rule 567—42.1(455B):
	1.	Failure to submit a monitoring report after a system properly conducts monitoring in a timely manner.
	2.	Failure to submit a completed assessment form after a system properly conducts an assessment in a timely manner.
	3.	Failure to notify the department following an E. coli-positive sample as required by 41.2(1)“k”(1) in a timely manner.
	4.	Failure to submit the certification of completion of department-approved start-up procedure by a seasonal system.
	q. 	Best available technology (BAT). The U.S. Environmental Protection Agency (EPA) identifies, and the department has adopted, the following as the best technology, treatment techniques, or other means available for all systems in achieving compliance with the maximum contaminant level for E. coli in 41.2(1)“a.” The following is also identified as affordable technology, treatment techniques, or other means available to systems serving 10,000 or fewer people for achieving compliance with the E. coli maximum contaminant level.
	(1)	Well protection. Protection of wells from fecal contamination by appropriate placement and construction.
	(2)	Disinfectant residual. Maintenance of a disinfectant residual throughout the distribution system.
	(3)	Distribution system maintenance. Proper maintenance of the distribution system including appropriate pipe replacement and repair procedures, main flushing programs, proper operation and maintenance of storage tanks and reservoirs, cross-connection control, and continual maintenance of a minimum positive water pressure of 20 psi in all parts of the distribution system at all times.
	(4)	Filtration or disinfection. Filtration and disinfection of surface water or groundwater under the direct influence of surface water in accordance with 567—43.5(455B), 567—43.9(455B), and 567—43.10(455B), or disinfection of groundwater in accordance with rule 567—41.7(455B) using strong oxidants such as, but not limited to, chlorine, chlorine dioxide, or ozone.
	(5)	Wellhead protection program. For groundwater systems, compliance with the requirements of the department’s wellhead protection program.
	41.2(2) Giardia. Reserved.
	41.2(3) Heterotrophic plate count bacteria (HPC).
	a. 	Applicability. All public water systems that use a surface water source or source under the direct influence of surface water must provide treatment consisting of disinfection, as specified in 567—subrule 43.5(2), and filtration treatment which complies with 567—subrule 43.5(3). The heterotrophic plate count is an alternate method to demonstrate a detectable disinfectant residual in accordance with 567—paragraph 43.5(2)“d.”
	b. 	Maximum contaminant levels. Reserved.
	c. 	Monitoring requirements. Reserved.
	d. 	BAT. Reserved.
	e. 	Analytical methodology. Public water systems shall conduct heterotrophic plate count bacteria analysis in accordance with 567—subrule 43.5(2) and the following analytical method. Measurements for heterotrophic plate count bacteria must be conducted by a laboratory certified by the department to do such analysis, when heterotrophic plate count bacteria are being measured in lieu of a detectable residual disinfectant pursuant to 567—paragraph 43.5(2)“d.” In addition, the time from sample collection to initiation of analysis may not exceed eight hours, and the systems must hold the samples below 10 degrees Celsius during transit to the laboratory.
	(1)	Method. The heterotrophic plate count shall be performed in accordance with one of the following methods:
	1.	Method 9215B Pour Plate Method, Standard Methods for the Examination of Water and Wastewater, 18th edition, 1992, 19th edition, 1995, 20th edition, 1998, 21st edition, 2005, and 22nd edition, 2012. The cited method in any of these editions may be used. Standard Methods Online method 9215 B-04 may be used.
	2.	SimPlate Method, “IDEXX SimPlate TM HPC Test Method for Heterotrophs in Water,” November 2000, IDEXX Laboratories, Inc., One IDEXX Drive, Westbrook, ME 04092, telephone (800)321-0207.
	(2)	Reporting. The public water system shall report the results of heterotrophic plate count in accordance with 567—subparagraph 42.4(3)“c”(2).
	41.2(4) Macroscopic organisms and algae.
	a. 	Applicability. These rules apply to both community and noncommunity public water supply systems using surface water or groundwater under direct influence of surface water as defined by 567—subrule 43.5(1).
	b. 	Maximum contaminant levels (MCLs) for macroscopic organisms and algae. Finished water shall be free of any macroscopic organisms such as plankton, worms, or cysts. The finished water algal cell count shall not exceed 500 organisms per milliliter or 10 percent of the total cells found in the raw water, whichever is greater.
	c. 	Monitoring requirements. Reserved.
	d. 	BAT. Reserved.
	e. 	Analytical methodology. Measurement of the algal cells shall be in accordance with Method 10200F: Phytoplankton Counting Techniques, Standard Methods for the Examination of Water and Wastewater, 18th edition, pp.	10-13 to 10-16. Such measurement shall be required only when the department determines on the basis of complaints or otherwise that excessive algal cells may be present.
[ARC 9915B, IAB 12/14/11, effective 1/18/12; ARC 3735C, IAB 4/11/18, effective 5/16/18]
567—41.3(455B) Maximum contaminant levels (MCLs) and monitoring requirements for inorganic contaminants other than lead or copper.
	41.3(1) MCLs and other requirements for inorganic contaminants.
	a. 	Applicability. Maximum contaminant levels for inorganic contaminants (IOCs) specified in 41.3(1)“b” apply to community water systems and nontransient noncommunity water systems as specified herein. The maximum contaminant level specified for fluoride applies only to community water systems and nontransient noncommunity systems which primarily serve children (child care facilities and schools). The maximum contaminant levels specified for nitrate, nitrite, and total nitrate and nitrite apply to community, nontransient noncommunity, and transient noncommunity water systems. At the discretion of the department, nitrate levels not to exceed 20.0 mg/L may be allowed in a noncommunity water system if the supplier of water demonstrates to the satisfaction of the department that:
	(1)	Such water will not be available to children under 6 months of age; and
	(2)	The system is meeting the public notification requirements of rule 567—42.1(455B), including continuous posting of the fact that nitrate levels exceed 10 mg/L and the potential health effects of exposure; and
	(3)	The following public health authorities will be notified annually of nitrate levels that exceed 10 mg/L, in addition to the reporting requirements of 567—Chapters 41 and 42: county board of health, county health department, county sanitarian, county public health administrator, and Iowa department of public health; and
	(4)	No adverse health effects shall result.
The requirements also contain monitoring requirements, best available technology (BAT) identification, and analytical method requirements pursuant to 41.3(1)“c,” and 567—paragraphs 41.3(1)“e” and 43.3(10)“b,” respectively.
	b. 	Maximum contaminant levels for inorganic chemicals (IOCs).
	(1)	IOC MCLs. The following table specifies the MCLs for IOCs:

Contaminant	EPA Contaminant Code	Maximum Contaminant Level (mg/L)	
Antimony	1074	0.006	
Arsenic*	1005	0.010	
Asbestos	1094	7 million fibers/liter
(longer than 10 micrometers in length)	
Barium	1010	2	
Beryllium	1075	0.004	
Cadmium	1015	0.005	
Chromium	1020	0.1	
Cyanide (as free Cyanide)	1024	0.2	
Fluoride**	1025	4.0	
Mercury	1035	0.002	
Nitrate	1040	10 (as nitrogen)	
Nitrite	1041	1.0 (as nitrogen)	
Total Nitrate and Nitrite	1038	10 (as nitrogen)	
Selenium	1045	0.05	
Thallium	1085	0.002	
*The arsenic MCL changed from 0.05 mg/L to 0.010 mg/L on January 23, 2006.
**The recommended fluoride level is 0.7 milligrams per liter as published by the U.S. Department of Health and Human Services, Public Health Service (July-August 2015). At this optimum level in drinking water, fluoride has been shown to have beneficial effects in reducing the occurrence of tooth decay.
	(2)	Compliance calculations. Compliance with 41.3(1)“b”(1) shall be determined based on the analytical result(s) obtained at each source/entry point. When the department requires a system to collect nitrate or nitrite samples in its distribution system, compliance with 41.3(1)“b”(1) shall also be determined based on the analytical result(s) obtained at each discrete sampling point in the distribution system. Arsenic sampling results must be reported to the nearest 0.001 mg/L.
	1.	Sampling frequencies greater than annual (e.g., monthly or quarterly). For public water supply systems which are conducting monitoring at a frequency greater than annual, compliance with the maximum contaminant levels for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, selenium, and thallium is determined by a running annual average at any sampling point. If the average at any sampling point is greater than the MCL, then the system is out of compliance. If any one sample would cause the annual average to be exceeded, then the system is out of compliance immediately. Any sample below the method detection limit shall be calculated at zero for the purpose of determining the annual average. If a system fails to collect the required number of samples, compliance (average concentration) will be based on the total number of samples collected.
	2.	Sampling frequencies of annual or less. For public water supply systems which are monitoring annually, or less frequently, the system is out of compliance with the maximum contaminant levels for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, selenium, and thallium if the level of a contaminant at any sampling point is greater than the MCL. If a confirmation sample is required by the department, it must be collected as soon as possible from the same sampling location, but not to exceed two weeks, and the determination of compliance will be based on the average of the two samples. If a system fails to collect the required number of samples, compliance (average concentration) will be based on the total number of samples collected.
	3.	Compliance calculations for nitrate and nitrite. Compliance with the maximum contaminant levels for nitrate and nitrite is determined based on one sample if the level of these contaminants is below the MCLs. If the level of nitrate or nitrite exceeds the MCLs in the initial sample, a confirmation sample may be required in accordance with 41.3(1)“c”(7)“2,” and compliance shall be determined based on the average of the initial and confirmation samples.
	(3)	Additional requirements. The department may assign additional requirements as deemed necessary to protect the public health, including public notification requirements and earlier compliance dates than indicated in rule. When a system is not in compliance with an MCL as determined in subparagraph 41.3(1)“b”(2), the supplier of the water shall notify the department according to 567—subrule 42.4(1) and give notice to the public according to 567—42.1(455B).
	c. 	Inorganic chemicals—monitoring requirements.
	(1)	Routine IOC monitoring (excluding asbestos, nitrate, and nitrite). Community public water supply systems and nontransient noncommunity water systems shall conduct monitoring to determine compliance with the MCLs specified in 41.3(1)“b” in accordance with this subrule. Transient noncommunity water systems shall conduct monitoring to determine compliance with the nitrate and nitrite maximum contaminant levels in 41.3(1)“b” as required by 41.3(1)“c”(5) and (6). All new systems or systems that use a new source of water must demonstrate compliance with the MCLs specified in 41.3(1)“b” within a period of time specified by the department. The system must also comply with the initial sampling frequencies specified by the department to ensure the system can demonstrate compliance with the MCLs. Routine and increased monitoring frequencies shall be conducted in accordance with the requirements in paragraph 41.3(1)“c.” A source of water that is determined by the department to be a new source/entry point is considered to be a new source for the purposes of this rule.
	(2)	Department designated sampling schedules: Each public water system shall monitor at the time designated by the department during each compliance period. The monitoring protocol is as follows:
	1.	Groundwater sampling points. Groundwater systems shall take a minimum of one sample at every entry point to the distribution system which is representative of each well after treatment (hereafter called a source/entry point) beginning in the compliance period starting January 1, 1993. The system shall take each sample at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.
	2.	Surface water sampling points. Surface water systems shall take a minimum of one sample at every entry point to the distribution system after any application of treatment or in the distribution system at a point which is representative of each source after treatment (hereafter called a source/entry point) beginning in the compliance period starting January 1, 1993. (For purposes of this paragraph, surface water systems include systems with a combination of surface and ground sources.) The system shall take each sample at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.
	3.	Multiple sources. If a public water supply system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating conditions (i.e., when water is representative of all sources being used).
	4.	Composite sampling. The department may reduce the total number of samples which must be analyzed by the use of compositing. In systems serving less than or equal to 3,300 persons, composite samples from a maximum of five samples are allowed, provided that the detection limit of the method used for analysis is less than one-fifth of the MCL. Compositing of samples must be done in the laboratory. If the concentration in the composite sample is greater than or equal to one-fifth of the MCL of any inorganic chemical, then a follow-up sample must be taken within 14 days at each sampling point included in the composite. These samples must be analyzed for the contaminants which exceeded one-fifth of the MCL in the composite sample. If duplicates of the original sample taken from each sampling point used in the composite are available, the system may use these duplicates instead of resampling, provided the holding time of the duplicate samples is not exceeded. The duplicate must be analyzed and the results reported to the department within 14 days after completing analysis of the composite sample. If the population served by the system is greater than 3,300 persons, then compositing may only be permitted by the department as sampling points within a single system. In systems serving less than or equal to 3,300 persons, the department may permit compositing among different systems provided the five-sample limit is maintained. Detection limits for each inorganic contaminant analytical method are contained in 41.3(1)“e”(1).
	(3)	Asbestos routine and repeat monitoring frequency. The frequency of monitoring conducted to determine compliance with the maximum contaminant level for asbestos specified in 41.3(1)“b” shall be conducted as follows:
	1.	Initial sampling frequency. Each community and nontransient noncommunity water system is required to monitor for asbestos during the first three-year compliance period of each nine-year compliance cycle beginning in the compliance period starting January 1, 1993.
	2.	Sampling during waiver. If the public water supply system believes it is not vulnerable to either asbestos contamination in its source water or due to corrosion of asbestos-cement pipe, or both, it may apply for a waiver of the monitoring requirement in 41.3(1)“c”(3)“1.” If the department grants the waiver, the system is not required to monitor.
	3.	Bases of an asbestos waiver. The department may grant a waiver based on a consideration of potential asbestos contamination of the water source, the use of asbestos-cement pipe for finished water distribution, and the corrosive nature of the water.
	4.	Effect of an asbestos waiver. A waiver remains in effect until the completion of the three-year compliance period. Systems not receiving a waiver must monitor in accordance with 41.3(1)“c”(3)“1.”
	5.	Distribution system vulnerability for asbestos. A public water supply system vulnerable to asbestos contamination due solely to corrosion of asbestos-cement pipe shall take one sample at a tap served by asbestos-cement pipe and under conditions where asbestos contamination is most likely to occur.
	6.	Source water vulnerability for asbestos. A public water supply system vulnerable to asbestos contamination due solely to source water shall monitor in accordance with the provision of 41.3(1)“c”(2).
	7.	Combined asbestos vulnerability. A public water supply system vulnerable to asbestos contamination due both to its source water supply and corrosion of asbestos-cement pipe shall take one sample at a tap served by asbestos-cement pipe and under conditions where asbestos contamination is most likely to occur.
	8.	Exceedance of the asbestos MCL. A public water supply system which exceeds the maximum contaminant levels as determined in 41.3(1)“b” shall monitor quarterly beginning in the next quarter after the violation occurred.
	9.	Asbestos reliably and consistently below the MCL. The department may decrease the quarterly monitoring requirement to the frequency specified in 41.3(1)“c”(3)“1” provided the system is reliably and consistently below the maximum contaminant level. In no case can the department make this determination unless a groundwater system takes a minimum of two quarterly samples and a surface (or combined surface/ground) water system takes a minimum of four quarterly samples.
	10.	Grandfathered asbestos data. If monitoring data collected after January 1, 1990, are generally consistent with the requirements of 41.3(1)“c”(3), then the department may allow public water supply systems to use that data to satisfy the monitoring requirement for the initial compliance period beginning January 1, 1993.
	(4)	Monitoring frequency for other IOCs. The frequency of monitoring conducted to determine compliance with the maximum contaminant levels in 41.3(1)“b” for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, selenium, and thallium shall be as follows:
	1.	IOCs sampling frequency. Groundwater systems shall take one sample at each sampling point once every three years. Surface water systems (or combined surface/groundwater systems) shall take one sample annually at each sampling point.
	2.	IOC sampling waiver. The public water supply system may apply for a waiver from the monitoring frequencies specified in 41.3(1)“c”(4)“1.”
	3.	IOC sampling during a waiver. A condition of the waiver shall require that a public water supply system shall take a minimum of one sample while the waiver is effective. The term during which the waiver is effective shall not exceed one compliance cycle (i.e., nine years).
	4.	Bases of an IOC waiver and grandfathered data. The department may grant a waiver provided surface water systems have monitored annually for at least three years and groundwater systems have conducted a minimum of three rounds of monitoring. (At least one sample shall have been taken since January 1, 1990.) Both surface and groundwater systems shall demonstrate that all previous analytical results were less than the maximum contaminant level. Systems that use a new water source are not eligible for a waiver until three rounds of monitoring from the new source have been completed. Systems may be granted a waiver for monitoring of cyanide, provided that the department determines that the system is not vulnerable due to lack of any industrial source of cyanide.
	5.	Bases of the IOC sampling frequency during a waiver. In determining the appropriate reduced monitoring frequency, the department will consider: reported concentrations from all previous monitoring; the degree of variation in reported concentrations; and other factors which may affect contaminant concentrations such as changes in groundwater pumping rates, changes in the system’s configuration, changes in the system’s operating procedures, or changes in stream flows or characteristics.
	6.	Effect of an IOC waiver. A decision to grant a waiver shall be made in writing and shall include the basis for the determination. The determination may be initiated by the department or upon an application by the public water supply system. The public water supply system shall specify the basis for its request. The department may review and, where appropriate, revise its determination of the appropriate monitoring frequency when the system submits new monitoring data or when other data relevant to the system’s appropriate monitoring frequency become available.
	7.	Exceedance of an IOC MCL. Public water supply systems which exceed the maximum contaminant levels as calculated in 41.3(1)“b” shall monitor quarterly beginning in the next quarter after the violation occurred.
	8.	IOCs reliably and consistently below the MCL. The department may decrease the quarterly monitoring requirement to the frequencies specified in 41.3(1)“c”(4)“1” and “3” provided it has determined that the public water supply system is reliably and consistently below the maximum contaminant level. In no case can the department make this determination unless a groundwater system takes a minimum of two quarterly samples and a surface water system takes a minimum of four quarterly samples.
	(5)	Routine and repeat monitoring frequency for nitrates. All public water supply systems (community; nontransient noncommunity; and transient noncommunity systems) shall monitor to determine compliance with the maximum contaminant level for nitrate in 41.3(1)“b.”
	1.	Initial nitrate sampling. Community and nontransient noncommunity water systems served by groundwater systems shall monitor annually beginning January 1, 1993; systems served by surface water shall monitor quarterly beginning January 1, 1993. Transient noncommunity water systems shall monitor annually beginning January 1, 1993.
	2.	Groundwater repeat nitrate sampling frequency. For community and noncommunity water systems, the repeat monitoring frequency for groundwater systems shall be:
	●	Quarterly for at least one year following any one sample in which the concentration is greater than or equal to 5.0 mg/L as N. The department may allow a groundwater system to reduce the sampling frequency to annually after four consecutive quarterly samples are reliably and consistently less than 5.0 mg/L as N.
	●	Monthly for at least one year following any one sample in which the concentration is greater than or equal to 10.0 mg/L as N.
3. Surface water repeat nitrate sampling frequency. For community and noncommunity water systems, the department may allow a surface water system to reduce the sampling frequency to:
	●	Annually if all analytical results from four consecutive quarters are less than 5.0 mg/L as N.
	●	Quarterly for at least one year following any one sample in which the concentration is greater than or equal to 5.0 mg/L as N. The department may allow a surface water system to reduce the sampling frequency to annually after four consecutive quarterly samples are reliably and consistently less than 5.0 mg/L as N.
	●	Monthly for at least one year following any nitrate MCL exceedance.
4. Scheduling annual nitrate repeat samples. After the initial round of quarterly sampling is completed, each community and nontransient noncommunity system which is monitoring annually shall take subsequent samples during the quarter(s) which previously resulted in the highest analytical result.
	(6)	Routine and repeat monitoring frequency for nitrite. All public water supply systems (community; nontransient noncommunity; and transient noncommunity systems) shall monitor to determine compliance with the maximum contaminant level for nitrite in 41.3(1)“b.”
	1.	Initial nitrite sampling. All public water systems shall take one sample at each sampling point in the compliance period beginning January 1, 1993, and ending December 31, 1995.
	2.	Nitrite repeat monitoring. After the initial sample, systems where an analytical result for nitrite is less than 0.50 mg/L as N shall monitor at the frequency specified by the department.
	3.	Nitrite increased monitoring. For community, nontransient noncommunity, and transient noncommunity water systems, the repeat monitoring frequency for any water system shall be:
	●	Quarterly for at least one year following any one sample in which the concentration is greater than or equal to 0.50 mg/L as N. The department may allow a system to reduce the sampling frequency to annually after determining the system is reliably and consistently less than 0.50 mg/L.
	●	Monthly for at least one year following any nitrite MCL exceedance.
4. Scheduling of annual nitrite repeat samples. Systems which are monitoring annually shall take each subsequent sample during the quarter(s) which previously resulted in the highest analytical result.
	(7)	Confirmation sampling.
	1.	Deadline for IOCs confirmation samples. Where the results of an analysis for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium, or thallium indicate an exceedance of the maximum contaminant level, the department may require that one additional sample be collected as soon as possible after the initial sample was taken (but not to exceed two weeks) at the same sampling point.
	2.	Deadline for nitrate and nitrite confirmation samples. Where nitrate or nitrite sampling results indicate an exceedance of the maximum contaminant level and the sampling frequency is quarterly or annual, the system shall take a confirmation sample within 24 hours of the system’s receipt of notification of the analytical results of the first sample. Public water supply systems unable to comply with the 24-hour sampling requirement must immediately notify the consumers served by the area served by the public water system in accordance with 567—42.1(455B) Tier 1 public notice and complete an analysis of a confirmation sample within two weeks of notification of the analytical results of the first sample. Where the sampling frequency is monthly, a confirmation sample will not be used to determine compliance with the MCL.
	3.	Rescinded IAB 1/7/04, effective 2/11/04.
	4.	Compliance calculations and confirmation samples. If a required confirmation sample as collected within the time specified in 41.3(1)“c”(7)“1” is taken for any contaminant, then the results of the initial and confirmation sample shall be averaged. The resulting average shall be used to determine the system’s compliance in accordance with 41.3(1)“b.” The department has the discretion to invalidate results of obvious sampling errors.
	(8)	Designation of increased sampling frequency. The department may require more frequent monitoring than specified in 41.3(1)“c”(3) through (6) or may require confirmation samples for positive and negative results at its discretion. Public water supply systems may apply to conduct more frequent monitoring than the minimum monitoring frequencies specified in this subrule. Any increase or decrease in monitoring under this subparagraph will be designated in an operation permit or administrative order. To increase or decrease such frequency, the department shall consider the following factors:
	1.	Reported concentrations from previously required monitoring,
	2.	The degree of variation in reported concentrations,
	3.	Blending or treatment processes conducted for the purpose of complying with a maximum contaminant level, treatment technique, or action level, and
	4.	Other factors include changes in pumping rates in groundwater supplies or significant changes in the system’s configuration, operating procedures, source of water and changes in streamflows.
	(9)	Grandfathered data. For the initial analysis required by 41.3(1)“c,” data for surface waters acquired within one year prior to the effective date and data for groundwaters acquired within three years prior to the effective date of 41.3(1)“c” may be substituted at the discretion of the department.
	d. 	Best available treatment technologies (BATs) for IOCs. Rescinded IAB 8/11/99, effective 9/15/99.
	e. 	Analytical methodology.
	(1)	Analytical methods for IOCs. Analysis for the listed inorganic contaminants shall be conducted using the following methods, or their equivalent as determined by EPA. Criteria for analyzing arsenic, barium, beryllium, cadmium, chromium, copper, lead, nickel, selenium, sodium, and thallium with digestion or directly without digestion, and other analytical test procedures are contained in Technical Notes on Drinking Water Methods, EPA-600/R-94-173, October, 1994. This document is available from the National Technical Information Service, NTIS PB95-104766, U.S. Department of Commerce, 5285 Port Royal Road, Springfield, VA 22161. The toll-free number is (800)553-6847.
INORGANIC CONTAMINANTS ANALYTICAL METHODS

Contaminant	Methodology15	EPA	ASTM3	SM	SM Online26	Other	Detection Limit,
mg/L	
Antimony	Atomic absorption; furnace	 	 	3113B4, 27, 33	3113 B-04, B-10	 	0.003	
 	Atomic absorption; platform	200.92	 	 	 	 	0.000812	
 	ICP-Mass spectrometry	200.82	 	 	 	 	0.0004	
 	Atomic absorption; hydride	 	D3697-92, 02, 07, 12	 	 	 	0.001	
 	Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)	200.5, Revision 4.228	 	 	 	 	 	
Arsenic16	ICP-Mass spectrometry	200.82	 	 	 	 	0.0014	
 	Atomic absorption; platform	200.92	 	 	 	 	0.000515	
 	Atomic absorption; furnace	 	D2972-97C, 03C, 08C	3113B4, 27, 33	3113 B-04, B-10	 	0.001	
 	Atomic absorption; hydride	 	D2972-97B, 03B, 08B	3114B4, 27, 33	3114 B-09	 	0.001	
 	Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)	200.5, Revision 4.228	 	 	 	 	 	
Asbestos	Transmission electron microscopy	100.19	 	 	 	 	0.01 MFL	
 	Transmission electron microscopy	100.210	 	 	 	 	 	
Barium	Inductively coupled plasma	200.72	 	3120B18, 27, 33	3120 B-99	 	0.002	
 	ICP-Mass spectrometry	200.82	 	 	 	 	 	
 	Atomic absorption; direct	 	 	3111D4, 27, 33	3111 D-99	 	0.1	
 	Atomic absorption; furnace	 	 	3113B4, 27, 33	3113 B-04, B-10	 	0.002	
 	Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)	200.5, Revision 4.228	 	 	 	 	 	
Beryllium	Inductively coupled plasma	200.72	 	3120B18, 27, 33	3120 B-99	 	0.0003	
 	ICP-Mass spectrometry	200.82	 	 	 	 	0.0003	
 	Atomic absorption; platform	200.92	 	 	 	 	0.0000212	
 	Atomic absorption; furnace	 	D3645-97B, 03B, 08B	3113B4, 27, 33	3113 B-04, B-10	 	0.0002	
 	Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)	200.5, Revision 4.228	 	 	 	 	 	
Cadmium	Inductively coupled plasma	200.72	 	 	 	 	0.001	
 	ICP-Mass spectrometry	200.82	 	 	 	 	 	
 	Atomic absorption; platform	200.92	 	 	 	 	 	
 	Atomic absorption; furnace	 	 	3113B4, 27, 33	3113 B-04, B-10	 	0.0001	
 	Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)	200.5, Revision 4.228	 	 	 	 	 	
Chromium	Inductively coupled plasma	200.72	 	3120B18, 27, 33	3120 B-99	 	0.007	
 	ICP-Mass spectrometry	200.82	 	 	 	 	 	
 	Atomic absorption; platform	200.92	 	 	 	 	 	
 	Atomic absorption; furnace	 	 	3113B4, 27, 33	3113 B-04, B-10	 	0.001	
 	Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)	200.5, Revision 4.228	 	 	 	 	 	
Cyanide	Manual distillation (followed by one of the following four analytical methods:)	 	D2036-98A, D2036-06A	4500-CN-C18,27, 33	 	 	 	
 	Spectrophotometric; amenable14	 	D2036-98B, D2036-06B	4500-CN-G18,27, 33	4500-CN-G-99	 	0.02	
 	Spectrophotometric; manual13	 	D2036-98A, D2036-06A	4500-CN-E18,27, 33	4500-CN-E-99	I-3300-855	0.02	
 	Spectrophotometric; semi-automated13	335.46	 	 	 	 	0.005	
 	Selective electrode13	 	 	4500-CN-F18, 27, 33	4500-CN-F-99	 	0.05	
 	UV, distillation, spectrophotometric22	 	 	 	 	Kelada 0120	0.0005	
 	Micro distillation, flow injection, spectrophotometric13	 	 	 	 	QuikChem
10-204-00-1
-X21	0.0006	
 	Ligand exchange with amperometry14	 	D6888-04	 	 	OIA-1677, DW25	0.0005	
 	Gas chromatography/mass spectrometry headspace	 	 	 	 	ME355.0129	 	
Fluoride	Ion chromatography	300.06, 300.123	D4327-97, 03, 11	4110B18, 27, 33	4110 B-00	 	 	
 	Manual distillation; colorimetric; SPADNS	 	 	4500F-B,D18,27, 33	4500 F-B,D-97	 	 	
 	Manual electrode	 	D1179-93B, 99B, D1179-04B, 10B	4500F-C18, 27, 33	4500 F-C-97	 	 	
 	Automated electrode	 	 	 	 	380-75WE11	 	
 	Automated alizarin	 	 	4500F-E18, 27, 33	4500 F-E-97	129-71W11	 	
 	Capillary ion electrophoresis	 	 	 	 	D6508, Rev.224	 	
 	Arsenite-free colorimetric; SPADNS	 	 	 	 	Hach SPADNS 2 Method 1022531	 	
Magnesium	Atomic absorption; direct	 	D511-93, 03B, 09B, 14B	3111B4, 27, 33	3111 B-99	 	 	
 	ICP	200.71	 	3120B18, 27, 33	3120 B-99	 	 	
 	Complexation Titrimetric Methods	 	D511-93, 03A, 09A, 14B	3500-Mg E4	 	 	 	
 	 	 	 	3500-Mg B19, 27, 33	3500-Mg B-97	 	 	
 	Ion chromatography	 	D6919-03, 09	 	 	 	 	
 	Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)	200.5, Revision 4.228	 	 	 	 	 	
Mercury	Manual, cold vapor	245.12	D3223-97, 02, 12	3112B4, 27, 33	3112 B-09	 	0.0002	
 	Automated, cold vapor	245.21	 	 	 	 	0.0002	
 	ICP-Mass spectrometry	200.82	 	 	 	 	 	
Nickel	Inductively coupled plasma	200.72	 	3120B18, 27, 33	3120 B-99	 	0.005	
 	ICP-Mass spectrometry	200.82	 	 	 	 	0.0005	
 	Atomic absorption; platform	200.92	 	 	 	 	0.000612	
 	Atomic absorption; direct	 	 	3111B4, 27, 33	3111 B-99	 	 	
 	Atomic absorption; furnace	 	 	3113B4, 27, 33	3113 B-04, 10	 	0.001	
 	Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)	200.5, Revision 4.228	 	 	 	 	 	
Nitrate	Ion chromatography	300.06, 300.123	D4327-97, 03, 11	4110B18, 27, 33	4110 B-00	B-10118	0.01	
 	Automated cadmium reduction	353.26	D3867-90A	4500-NO3-F18, 27, 33	4500-NO3-F-00	 	0.05	
 	Ion selective electrode	 	 	4500-NO3-D18, 27, 33	4500-NO3-D-00	6017	1	
 	Manual cadmium reduction	 	D3867-90B	4500-NO3-E18, 27, 33	4500-NO3-E-00	 	0.01	
 	Capillary ion electrophoresis	 	 	 	 	D6508, Rev.224	0.076	
 	Reduction/colorimetric	 	 	 	 	Systea Easy (1-Reagent)30 NECi Nitrate-
Reductase34	 	
 	Colorimetric; direct	 	 	 	 	Hach TNTplusTM 835/836 Method 1020632	 	
Nitrite	Ion chromatography	300.06, 300.123	D4327-97, 03, 11	4110B18, 27, 33	4110 B-00	B-10118	0.004	
 	Automated cadmium reduction	353.26	D3867-90A	4500-NO3-F18, 27, 33	4500-NO3-F-00	 	0.05	
 	Manual cadmium reduction	 	D3867-90B	4500-NO3-E18, 27, 33	4500-NO3-E-00	 	0.01	
 	Spectrophotometric	 	 	4500-NO2-B18, 27, 33	4500-NO2-B-00	 	0.01	
 	Capillary ion electrophoresis	 	 	 	 	D6508, Rev.	224	0.103	
 	Reduction/colorimetric	 	 	 	 	Systea Easy (1-Reagent)30
NECi Nitrate-
Reductase34	 	
Selenium	Atomic absorption; hydride	 	D3859-98, 03A, 08A	3114B4, 27, 33	3114 B-09	 	0.002	
 	ICP-Mass spectrometry	200.82	 	 	 	 	 	
 	Atomic absorption; platform	200.92	 	 	 	 	 	
 	Atomic absorption; furnace	 	D3859-98, 03B, 08B	3113B4, 27, 33	3113 B-04, 10	 	0.002	
 	Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)	200.5, Revision 4.228	 	 	 	 	 	
Sodium	Inductively coupled plasma	200.72	 	 	 	 	 	
 	Atomic absorption; direct	 	 	3111B4, 27, 33	3111 B-99	 	 	
 	Ion chromatography	 	D6919-03, 09	 	 	 	 	
 	Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)	200.5, Revision 4.228	 	 	 	 	 	
Thallium	ICP-Mass spectrometry	200.82	 	 	 	 	 	
 	Atomic absorption; platform	200.92	 	 	 	 	0.000712	

<fo:wrapper font-size="8pt">The procedures shall be done in accordance with the documents listed below. The incorporation by reference of the following documents was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies of the documents may be obtained from the sources listed below. Information regarding obtaining these documents can be obtained from the Safe Drinking Water Hotline at (800)426-4791. Documents may be inspected at EPA’s Drinking Water Docket, EPA West, 1301 Constitution Avenue, NW, Room B102, Washington, DC 20460 (telephone: (202)566-2426); or at the Office of Federal Register, 800 North Capitol Street, NW, Suite 700, Washington, DC.</fo:wrapper>	
1“Methods for Chemical Analysis of Water and Wastes,” EPA-600/4-79-020, March 1983. Available at NTIS, PB84-128677.
2“Methods for the Determination of Metals in Environmental Samples—Supplement I,” EPA-600/R-94-111, May 1994. Available at NTIS, PB95-125472.
3Annual Book of ASTM Standards, 1994, 1996, 1999 or 2003, Vols. 11.01 and 11.02, American Society for Testing and Materials (ASTM) International; the methods listed are the only versions that may be used. Copies may be obtained from ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428.
418th and 19th editions of Standard Methods for the Examination of Water and Wastewater, 1992 and 1995, respectively, American Public Health Association; either edition may be used. Copies may be obtained from the American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710.
5Techniques of Water Resources Investigation of the U.S. Geological Survey, Book 5, Chapter A-1, 3rd edition, 1989, Method I-3300-85. Available from Information Services, U.S. Geological Survey, Federal Center, Box 25286, Denver, CO 80225-0425.
6“Methods for the Determination of Inorganic Substances in Environmental Samples,” EPA-600-R-93-100, August 1993. Available at NTIS, PB94-120821.
7The procedure shall be done in accordance with the Technical Bulletin 601, “Standard Method of Test for Nitrate in Drinking Water,” July 1994, PN221890-001, Analytical Technology, Inc.	Copies may be obtained from ATI Orion, 529 Main Street, Boston, MA 02129.
8Method B-1011, “Waters Test Method for Determination of Nitrite/Nitrate in Water Using Single Column Ion Chromatography,” August 1987. Copies may be obtained from Waters Corporation, Technical Services Division, 34 Maple Street, Milford, MA 01757; telephone: (508)482-2131.
9Method 100.1, “Analytical Method for Determination of Asbestos Fibers in Water,” EPA-600/4-83-043, EPA, September 1983. Available at NTIS, PB83-260471.
10Method 100.2, “Determination of Asbestos Structure Over 10 Microns in Length in Drinking Water,” EPA-600/R-94-134, June 1994. Available at NTIS, PB94-201902.
11Industrial Method No.	129-71W, “Fluoride in Water and Wastewater,” December 1972, and Method No.	380-75WE, “Fluoride in Water and Wastewater,” February 1976, Technicon Industrial Systems. Copies may be obtained from Bran & Luebbe, 1025 Busch Parkway, Buffalo Grove, IL 60089.
12Lower MDLs are reported using stabilized temperature graphite furnace atomic absorption.
13Screening method for total cyanides.
14Measures “free” cyanides when distillation, digestion, or ligand exchange is omitted.
15Because MDLs reported in EPA Methods 200.7 and 200.9 were determined using a 2X preconcentration step during sample digestion, MDLs determined when samples are analyzed by direct analysis (i.e., no sample digestion) will be higher. For direct analysis of cadmium by Method 200.7, sample preconcentration using pneumatic nebulization may be required to achieve lower detection limits. Preconcentration may also be required for direct analysis of antimony and thallium by Method 200.9, and antimony by Method 3113B, unless multiple in-furnace depositions are made.
16If ultrasonic nebulization is used in the determination of arsenic by Method 200.8, the arsenic must be in the pentavalent state to provide uniform signal response. For direct analysis of arsenic with Method 200.8 using ultrasonic nebulization, samples and standards must contain 1 mg/L of sodium hypochlorite.
17Reserved.
18The 18th, 19th, and 20th editions of Standard Methods for the Examination of Water and Wastewater, 1992, 1995, and 1998, respectively, American Public Health Association; any edition may be used, except that the versions of 3111B, 3111D, 3113B, and 3114B in the 20th edition may not be used. Copies may be obtained from the American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710.
19The 20th edition of Standard Methods for the Examination of Water and Wastewater, 1998, American Public Health Association. Copies may be obtaining from the American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710.
20The description for the Kelada 01 Method, “Kelada Automated Test Methods for Total Cyanide, Acid Dissociable Cyanide, and Thiocyanate,” Revision 1.2, August 2001, EPA #821-B-01-009 for cyanide is available from NTIS PB 2001-108275. Note: A 450W UV lamp may be used in this method instead of the 550W lamp specified if it provides performance within the quality control acceptance criteria of the method in a given instrument. Similarly, modified flow cell configurations and flow conditions may be used in the method, provided that the quality control acceptance criteria are met.
21The description for the QuikChem Method 10-204-00-1-X, “Digestion and distillation of total cyanide in drinking water and wastewaters using MICRO DIST and determination of cyanide by flow injection analysis,” Revision 2.1, November 30, 2000, for cyanide is available from Lachat Instruments, 6645 W. Mill Road, Milwaukee, WI 53218, telephone (414)358-4200.
22Measures total cyanides when UV-digestor is used, and “free” cyanides when UV-digestor is bypassed.
23“Methods for the Determination of Organic and Inorganic Compounds in Drinking Water,” Volume 1, EPA 815-R-00-014, August 2000. Available at NTIC, PB2000-106981.
24Method D6508, Rev.	2, “Test Method for Determination of Dissolved Inorganic Anions in Aqueous Matrices Using Capillary Ion Electrophoresis and Chromate Electrolyte,” available from Waters Corp., 34 Maple Street, Milford, MA 01757; telephone: (508)482-2131; fax: (508)482-3625.
25Method OIA-1677, DW “Available Cyanide by Flow Injection, Ligand Exchange, and Amperometry,” January 2004. EPA-821-R-04-001. Available from ALPKEM, a division of OI Analytical, P.O. Box 9010, College Station, TX 77542-9010.
26Standard Methods Online is available at www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only online versions that may be used.
27Standard Methods for the Examination of Water and Wastewater, 21st edition (2005). Available from American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710.
28EPA Method 200.5, Revision 4.2: “Determination of Trace Elements in Drinking Water by Axially Viewed Inductively Coupled Plasma-Atomic Emission Spectrometry,” 2003. EPA/600/R-06/115. Available at www.nemi.gov.
29Method ME355.01, Revision 1.0, “Determination of Cyanide in Drinking Water by GC/MS Headspace,” May 26, 2009. Available at www.nemi.gov or from H & E Testing Laboratory, 221 State Street, Augusta, ME 04333; telephone: (207)287-2727.
30Systea Easy (1-Reagent), “Systea Easy (1-Reagent) Nitrate Method,” February 4, 2009. Available at www.nemi.gov or from Systea Scientific, LLC, 900 Jorie Blvd., Suite 35, Oak Brook, IL 60523.
31Hach Company Method, “Hach Company SPADNS 2 (Arsenic-free) Fluoride Method 10225 – Spectrophotometric Measurement of Fluoride in Water and Wastewater,” January 2011. 5600 Lindbergh Drive, P.O. Box 389, Loveland, CO 80539. Available at www.hach.com.
32Hach Company Method, “Hach Company TNTplusTM 835/836 Nitrate Method 10206 – Spectrophotometric Measurement of Nitrate in Water and Wastewater,” January 2011. 5600 Lindbergh Drive, P.O. Box 389, Loveland, CO 80539. Available at www.hach.com.
33Standard Methods for the Examination of Water and Wastewater, 22nd edition (2012), American Public Health Association. Available from the American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710.
34Nitrate Elimination Company, Inc.	(NECi). “Method for Nitrate Reductase Nitrate-Nitrogen Analysis of Drinking Water,” February 2016. Superior Enzymes, Inc., 334 Hecla Street, Lake Linden, MI 49945.
	(2)	Sampling methods for IOCs. Sample collection for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, nitrate, nitrite, selenium, and thallium under this subparagraph shall be conducted using the sample preservation, container, and maximum holding time procedures specified in the table below:
SAMPLING METHODS FOR IOCs

Contaminant	Preservative1	Container2	Time3	
Antimony	HNO3	P or G	6 months	
Arsenic	HNO3	P or G	6 months	
Asbestos	4 degrees C	P or G	48 hours for filtration5	
Barium	HNO3	P or G	6 months	
Beryllium	HNO3	P or G	6 months	
Cadmium	HNO3	P or G	6 months	
Chromium	HNO3	P or G	6 months	
Cyanide	4 degrees C, NaOH	P or G	14 days	
Fluoride	None	P or G	1 month	
Mercury	HNO3	P or G	28 days	
Nickel	HNO3	P or G	6 months	
Nitrate4	4 degrees C	P or G	48 hours	
Nitrate-Nitrite4	H2SO4	P or G	28 days	
Nitrite4	4 degrees C	P or G	48 hours	
Selenium	HNO3	P or G	6 months	
Thallium	HNO3	P or G	6 months	
1When indicated, samples must be acidified at the time of collection to pH < 2 with concentrated acid, or adjusted with sodium hydroxide to pH > 12. Samples collected for metals analysis may be preserved by acidification at the laboratory, using a 1:1 nitric acid solution (50 percent by volume), provided the shipping time and other instructions in Section 8.3 of EPA Methods 200.7, 200.8, and 200.9 are followed. When chilling is indicated, the sample must be shipped and stored at 4 degrees C or less.
2P: plastic, hard or soft; G: glass, hard or soft.
3In all cases, samples should be analyzed as soon after collection as possible. Follow additional (if any) information on preservation, containers, or holding times that is specified in the method.
4Nitrate may only be measured separate from nitrite in samples that have not been acidified. Measurement of acidified samples provides a total nitrate (sum of nitrate plus nitrite) concentration. Acidification of total nitrate (nitrate plus nitrite) samples must be done in the field at the time of sample collection.
5Instructions for containers, preservation procedures, and holding times as specified in Method 100.2 must be adhered to for all compliance analyses, including those conducted with Method 100.1.
	f. 	Unregulated inorganic chemicals. Rescinded IAB 1/7/04, effective 2/11/04.
	41.3(2) Other inorganic chemical contaminants. Reserved.
[ARC 9915B, IAB 12/14/11, effective 1/18/12; ARC 3735C, IAB 4/11/18, effective 5/16/18]
567—41.4(455B) Lead, copper, and corrosivity.
	41.4(1) Lead, copper, and corrosivity regulation by the setting of a treatment technique requirement. The lead and copper rules establish a treatment technique that includes requirements for corrosion control treatment, source water treatment, lead service line replacement, and public education. These requirements are triggered, in some cases, by lead and copper action levels measured in samples collected at consumers’ taps.
	a. 	Applicability. Unless otherwise indicated, each of the provisions of this subrule applies to community water systems and nontransient noncommunity water systems (hereinafter referred to as “water systems” or “systems”).
	b. 	Action levels.
	(1)	Lead action level. The lead action level is exceeded if the concentration of lead in more than 10 percent of tap water samples collected during any monitoring period conducted in accordance with 41.4(1)“c” is greater than 0.015 mg/L (i.e., if the “90th percentile” lead level is greater than 0.015 mg/L).
	(2)	Copper action level. The copper action level is exceeded if the concentration of copper in more than 10 percent of tap water samples collected during any monitoring period conducted in accordance with 41.4(1)“c” is greater than 1.3 mg/L (i.e., if the “90th percentile” copper level is greater than 1.3 mg/L).
	(3)	Calculation of 90th percentile. The 90th percentile lead and copper levels shall be computed as follows:
	1.	The results of all lead or copper samples taken during a monitoring period shall be placed in ascending order from the sample with the lowest concentration to the sample with the highest concentration. Each sampling result shall be assigned a number, ascending by single integers beginning with the number 1 for the sample with the lowest contaminant level. The number assigned to the sample with the highest contaminant level shall be equal to the total number of samples taken.
	2.	The number of samples taken during the monitoring period shall be multiplied by 0.9.
	3.	The contaminant concentration in the numbered sample yielded by this calculation is the 90th percentile contaminant level.
	4.	For water systems serving fewer than 100 people that collect five samples per monitoring period, the 90th percentile is computed by taking the average of the highest and second highest concentrations.
	5.	For a public water system that has been allowed by the department to collect fewer than five samples in accordance with 41.4(1)“c”(3), the sample result with the highest concentration is considered the 90th percentile value.
	c. 	Lead and copper tap water monitoring requirements.
	(1)	Sample site selection.
	1.	General. Public water supply systems shall complete a materials evaluation of their distribution systems by the date indicated in 41.4(1)“c”(4) in order to identify a pool of sampling sites that meets the requirements of this subrule, and which is sufficiently large to ensure that the water system can collect the number of lead and copper tap samples required in 41.4(1)“c”(3). All sites from which first-draw samples are collected shall be selected from this pool of targeted sampling sites. Sampling sites may not include faucets that have point-of-use or point-of-entry treatment devices designed to remove inorganic contaminants.
	2.	Information sources. A public water supply system shall use the information on lead, copper and galvanized steel that it is required to collect under 41.4(1)“f” as part of its responsibility for the special monitoring for corrosivity characteristics when conducting a materials evaluation. When an evaluation of the information collected is insufficient to locate the requisite number of lead and copper sampling sites that meet the targeting criteria in 41.4(1)“c”(1), the water system shall review all plumbing codes, permits, and records in the files of the building department(s) which indicate the plumbing materials that are installed within publicly and privately owned structures connected to the distribution system; all inspections and records of the distribution system that indicate the material composition of the service connections that connect a structure to the distribution system; and all existing water quality information, which includes the results of all prior analyses of the system or individual structures connected to the system, indicating locations that may be particularly susceptible to high lead or copper concentrations. In addition, the system shall seek to collect such information where possible in the course of its normal operations (e.g., checking service line materials when reading water meters or performing maintenance activities).
	3.	Tier 1 community sampling sites. The sampling sites selected for a community water system’s sampling pool (“tier 1 sampling sites”) shall consist of single-family structures that contain copper pipes with lead solder installed after 1982 or contain lead pipes; or are served by a lead service line. When multiple-family residences comprise at least 20 percent of the structures served by a water system, the system may include these types of structures in its sampling pool.
	4.	Tier 2 community sampling sites. Any community water system with insufficient tier 1 sampling sites shall complete its sampling pool with “tier 2 sampling sites,” consisting of buildings, including multiple-family residences that contain copper pipes with lead solder installed after 1982 or contain lead pipes; or are served by a lead service line.
	5.	Tier 3 community sampling sites. Any community water system with insufficient Tier 1 and Tier 2 sampling sites shall complete its sampling pool with “Tier 3 sampling sites,” consisting of single-family structures that contain copper pipes with lead solder installed before 1983. A community water system with insufficient Tier 1, Tier 2, and Tier 3 sampling sites shall complete its sampling pool with representative sites throughout the distribution system. A representative site is defined as a site in which the plumbing materials used at that site would be commonly found at other sites served by the water system.
	6.	Tier 1 NTNC sampling sites. The sampling sites selected for a nontransient noncommunity water system (“tier 1 sampling sites”) shall consist of buildings that: contain copper pipes with lead solder installed after 1982 or contain lead pipes; or are served by a lead service line.
	7.	Other NTNC sampling sites. A nontransient noncommunity water system with insufficient Tier 1 sites that meet the targeting criteria in 41.4(1)“c”(1)“6” shall complete its sampling pool with sampling sites that contain copper pipes with lead solder installed before 1983. If additional sites are needed to complete the sampling pool, the NTNC system shall use representative sites throughout the distribution system. A representative site is defined as a site in which the plumbing materials used at that site would be commonly found at other sites served by the water system.
	8.	LSL sampling sites. Any public water supply system whose distribution system contains lead service lines shall draw 50 percent of the samples it collects during each monitoring period from sites that contain lead pipes, or copper pipes with lead solder, and 50 percent of those samples from sites served by a lead service line. A water system that cannot identify a sufficient number of sampling sites served by a lead service line shall collect first-draw samples from all of the sites identified as being served by such lines.
	(2)	Sample collection methods.
	1.	Tap samples for lead and copper collected in accordance with this subparagraph, with the exception of lead service line samples collected under 567—subrule 43.7(4) and 41.4(1)“c”(2)“5,” shall be first-draw samples.
	2.	First-draw tap samples for lead and copper shall be one liter in volume and have stood motionless in the plumbing system of each sampling site for at least six hours. First-draw samples from residential housing shall be collected from the cold-water kitchen tap or bathroom sink tap. First-draw samples from a nonresidential building shall be collected at an interior tap from which water is typically drawn for consumption. Non-first-draw samples collected in lieu of first-draw samples pursuant to 41.4(1)“c”(2)“5” shall be one liter in volume and shall be collected at an interior tap from which water is typically drawn for consumption. First-draw samples may be collected by the system or the system may allow residents to collect first-draw samples after instructing the residents of the sampling procedures specified in this paragraph. To avoid problems of residents handling nitric acid, acidification of first-draw samples may be done up to 14 days after the sample is collected. After acidification to resolubilize the metals, the sample must stand in the original container for the time specified in the approved EPA method before the sample can be analyzed. If a system allows residents to perform sampling, the system may not challenge, based on alleged errors in sample collection, the accuracy of sampling results.
	3.	Service line samples collected to determine if the service line is directly contributing lead (as described in 567—subrule 43.7(4)) shall be one liter in volume and have stood motionless in the lead service line for at least six hours and be collected at the tap after flushing the volume of water between the tap and the lead service line. The volume of water shall be calculated based on the interior diameter and length of the pipe between the tap and the lead service line; tapping directly into the lead service line; or if the sampling site is a building constructed as a single-family residence, allowing the water to run until there is a significant change in temperature which would be indicative of water that has been standing in the lead service line.
	4.	A public water supply system shall collect each first-draw tap sample from the same sampling site from which it collected a previous sample. If, for any reason, the water system cannot gain entry to a sampling site in order to collect a follow-up tap sample, the system may collect the follow-up tap sample from another sampling site in its sampling pool as long as the new site meets the same targeting criteria, and is within reasonable proximity of the original site.
	5.	An NTNC system, or a CWS system that meets the criteria of 567—subparagraph 42.2(2)“b”(7) that does not have enough taps that can supply first-draw samples, as defined in 567—40.2(455B), may apply to the department in writing to substitute non-first-draw samples. Such systems must collect as many first-draw samples from appropriate taps as possible and identify sampling times and locations that would likely result in the longest standing time for the remaining sites. The department may waive the requirement for prior department approval of non-first-draw sample sites selected by the system, through written notification to the system.
	(3)	Number of samples. Water systems shall collect at least one sample during each monitoring period specified in 41.4(1)“c”(4) from the number of sites as listed in the column below titled “standard monitoring.” A system conducting reduced monitoring under 41.4(1)“c”(4) shall collect at least one sample from the number of sites specified in the column titled “reduced monitoring” during each monitoring period specified in 41.4(1)“c”(4). Such reduced monitoring sites shall be representative of the sites required for standard monitoring. A public water system that has fewer than five drinking water taps that can be used for human consumption meeting the sample site criteria of 41.4(1)“c”(1) to reach the required number of sample sites listed in 41.4(1)“c”(3) must collect at least one sample from each tap and then must collect additional samples from those taps on different days during the monitoring period to meet the required number of sites. Alternatively, the department may allow these systems to collect a number of samples less than the number of sites specified in 41.4(1)“c”(1), provided that 100 percent of all taps that can be used for human consumption are sampled. The department must approve this reduction of the minimum number of samples in writing based upon a request from the system or on-site verification by the department. The department may specify sampling locations when a system is conducting reduced monitoring.
REQUIRED NUMBER OF LEAD/COPPER SAMPLES

System Size	Standard Monitoring	Reduced Monitoring	
(Number of People Served)	(Number of Sites)	(Number of Sites)	
 	 	 	
greater than 100,000	100	50	
10,001 to 100,000	60	30	
3,301 to 10,000	40	20	
501 to 3,300	20	10	
101 to 500	10	5	
less than or equal to 100	5	5	
	(4)	Timing of monitoring.
1. Initial tap sampling. The first six-month monitoring period for small, medium-size and large systems shall begin on the following dates:

System Size (Number of People Served)	First Six-month Monitoring Period Begins on:	
 	 	
greater than 50,000 (large system)	January 1, 1992	
3,301 to 50,000 (medium system)	July 1, 1992	
less than or equal to 3,300 (small system)	July 1, 1993	
All large systems shall monitor during two consecutive six-month periods. All small and medium-size systems shall monitor during each six-month monitoring period until the system exceeds the lead or copper action level and is, therefore, required to implement the corrosion control treatment requirements under 567—paragraph 43.7(1)“a,” in which case the system shall continue monitoring in accordance with 41.4(1)“c”(4), or the system meets the lead and copper action levels during two consecutive six-month monitoring periods, in which case the system may reduce monitoring in accordance with 41.4(1)“c”(4).
2. Monitoring after installation of corrosion control and source water treatment. Large systems which install optimal corrosion control treatment pursuant to 567—subparagraph 43.7(1)“d”(4) shall monitor during two consecutive six-month monitoring periods by the date specified in 567—subparagraph 43.7(1)“d”(5). Small or medium-size systems which install optimal corrosion control treatment pursuant to 567—subparagraph 43.7(1)“e”(5) shall monitor during two consecutive six-month monitoring periods as specified in 567—subparagraph 43.7(1)“e”(6). Systems which install source water treatment shall monitor during two consecutive six-month monitoring periods by the date specified in 567—subparagraph 43.7(3)“a”(4).
	3.	Monitoring after the department specifies water quality parameter values for optimal corrosion control. After the department specifies the values for water quality control parameters under 567—paragraph 43.7(2)“f,” the system shall monitor during each subsequent six-month monitoring period, with the first monitoring period to begin on the date the department specifies the optimal values under 567—paragraph 43.7(2)“f.”
	4.	Reduced monitoring.
	●	A small or medium-size water system that meets the lead and copper action levels during each of two consecutive six-month monitoring periods may reduce the number of lead and copper samples according to 41.4(1)“c”(3) and reduce the frequency of sampling to once per year. A small or medium-size water system collecting fewer than five samples as specified in 41.4(1)“c”(3) that meets the lead and copper action levels during each of two consecutive six-month monitoring periods may reduce the frequency of sampling to once per year. The system may not ever reduce the number of samples required below the minimum of one sample per available tap. This sampling shall begin during the calendar year immediately following the end of the second consecutive six-month monitoring period.
	●	Any public water supply system that meets the lead action level and maintains the range of values for the water quality control parameters reflecting optimal corrosion control treatment specified by the department under 567—paragraph 43.7(2)“f” during each of two consecutive six-month monitoring periods may reduce the monitoring frequency to once per year and reduce the number of lead and copper samples according to 41.4(1)“c”(3), upon written approval by the department. This sampling shall begin during the calendar year immediately following the end of the second consecutive six-month monitoring period. The department shall review monitoring, treatment, and other relevant information submitted by the water system in accordance with 567—subrule 42.4(2), and shall notify the system in writing when it determines that the system is eligible to commence reduced monitoring. The department will review and, where appropriate, revise its determination when the system submits new monitoring or treatment data, or when other data relevant to the number and frequency of tap sampling becomes available.
	●	A small or medium-size water system that meets the lead and copper action levels during three consecutive years of monitoring may reduce the frequency of monitoring for lead and copper from annually to once every three years. Any water system that meets the lead action level and maintains the range of values for the water quality control parameters reflecting optimal corrosion control treatment specified by the department under 567—paragraph 43.7(2)“f” during three consecutive years of monitoring may reduce the frequency of monitoring from annually to once every three years if it receives written approval by the department. Samples collected once every three years shall be collected no later than every third calendar year. The department shall review monitoring, treatment, and other relevant information submitted by the water system in accordance with 567—subrule 42.4(2), and shall notify the system in writing when it determines that the system is eligible to reduce the monitoring frequency to once every three years. The department will review and, where appropriate, revise its determination when the system submits new monitoring or treatment data, or when other data relevant to the number and frequency of tap sampling becomes available.
	●	A water system that reduces the number and frequency of sampling shall collect these samples from sites included in the pool of targeted sampling sites identified in 41.4(1)“c”(1). Systems sampling annually or less frequently shall conduct the lead and copper tap sampling during the months of June through September, unless the department, at its discretion, has approved a different sampling period. If approved by the department, the period shall be no longer than four consecutive months and must represent a time of normal operation where the highest levels of lead are most likely to occur. The department shall designate a period that represents a time of normal operation for an NTNC system that does not operate during the months of June through September, and for which the period of normal operation where the highest levels of lead are most likely to occur is not known. This sampling shall begin during the period approved or designated by the department in the calendar year immediately following the end of the second consecutive six-month monitoring period for systems initiating annual monitoring and during the three-year period following the end of the third consecutive calendar year of annual monitoring for systems initiating triennial monitoring.
Systems monitoring annually that have been collecting samples during the months of June through September and that receive department approval to alter their sample collection period must collect their next round of samples during a time period that ends no later than 21 months after the previous round of sampling.
Systems monitoring triennially that have been collecting samples during the months of June through September and that receive department approval to alter the sampling collection period must collect their next round of samples during a time period that ends no later than 45 months after the previous round of sampling.
Subsequent rounds of sampling must be collected annually or triennially, as required by 41.4(1)“c.”
Small systems that have been granted waivers pursuant to 41.4(1)“c”(7), that have been collecting samples during the months of June through September and that receive department approval to alter their sample collection period as previously stated must collect their next round of samples before the end of the nine-year period.
	●	Any water system that demonstrates for two consecutive six-month monitoring periods that the 90th percentile tap water level computed under 41.4(1)“b”(3) is less than or equal to 0.005 mg/L for lead and is less than or equal to 0.65 mg/L for copper may reduce the number of samples in accordance with 41.4(1)“c”(3) and reduce the frequency of sampling to once every three calendar years, if approved by the department.
	●	A small or medium-size water system subject to reduced monitoring that exceeds the lead or copper action level shall resume sampling according to 41.4(1)“c”(4)“3” and collect the number of samples specified for standard monitoring in 41.4(1)“c”(3). Any such system shall also conduct water quality parameter monitoring in accordance with 41.4(1)“d”(2), (3), or (4), as appropriate, during the monitoring period in which it exceeded the action level. Any such system may resume annual monitoring for lead and copper at the tap at the reduced number of sites specified in 41.4(1)“c”(3) after it has completed two subsequent consecutive six-month rounds of monitoring that meet the criteria of 41.4(1)“c”(4)“4,” first bulleted paragraph, and may resume triennial monitoring for lead and copper at the reduced number of sites after it demonstrates through subsequent rounds of monitoring that it meets the criteria of either 41.4(1)“c”(4)“4,” third bulleted paragraph or fifth bulleted paragraph, and has received department approval.
Any water system subject to reduced monitoring frequency that fails to meet the lead action level during any four-month monitoring period or that fails to operate at or above the minimum value or within the range of values for the water quality control parameters specified by the department under 567—paragraph 43.7(2)“f” for more than nine days in any six-month period specified in 41.4(1)“d”(4) shall resume tap water sampling according to 41.4(1)“c”(4)“3,” collect the number of samples specified for standard monitoring in 41.4(1)“c”(3), and resume monitoring for water quality parameters within the distribution system in accordance with 41.4(1)“d”(4). This standard tap water sampling shall begin no later than the six-month period beginning January 1 of the calendar year following the lead action level exceedance or water quality parameter excursion. The system may resume reduced monitoring for lead and copper at the tap and for water quality parameters within the distribution system under the following conditions:
The system may resume annual monitoring for lead and copper at the tap at the reduced number of sites specified in 41.4(1)“c”(3) after it has completed two subsequent six-month rounds of monitoring that meet the criteria of 41.4(1)“c”(4)“4,” second bulleted paragraph, and upon written approval from the department to resume reduced annual monitoring. This sampling shall begin during the calendar year immediately following the end of the second consecutive six-month monitoring period.
The system may resume triennial monitoring for lead and copper at the tap at the reduced number of sites after it demonstrates through subsequent rounds of monitoring that it meets the criteria of either 41.4(1)“c”(4)“4,” third bulleted paragraph or fifth bulleted paragraph, and upon written approval from the department to resume triennial monitoring.
The system may reduce the number of water quality parameter tap water samples required in 41.4(1)“d”(5)“1” and the sampling frequency required in 41.4(1)“d”(5)“2.” Such a system may not resume triennial monitoring for water quality parameters at the tap until it demonstrates that it has requalified for triennial monitoring, pursuant to 41.4(1)“d”(5)“2.”
	●	Any water system subject to a reduced monitoring frequency under 41.4(1)“c”(4)“4” must notify the department in writing in accordance with 567—subparagraph 42.4(2)“a”(3) of any upcoming long-term change in treatment or addition of a new source as described in that subparagraph. The department must review and approve the addition of a new source or long-term change in water treatment before it is implemented by the system. The department may require the system to resume sampling pursuant to 41.4(1)“c”(4)“3” and collect the number of samples specified for standard monitoring under 41.4(1)“c”(3), or take other appropriate steps such as increased water quality parameter monitoring or reevaluation of its corrosion control treatment given the potentially different water quality considerations.
	(5)	Additional monitoring by systems. The results of any monitoring conducted in addition to the minimum requirements of 41.4(1)“c” shall be considered by the system and the department in making any determinations (i.e., calculating the 90th percentile lead or copper level) under this subrule.
	(6)	Invalidation of lead or copper tap water samples. A sample invalidated under this paragraph does not count toward determining the lead or copper 90th percentile levels under 41.4(1)“b”(3) or toward meeting the minimum monitoring requirements of 41.4(1)“c”(3).
1. The department may invalidate a lead or copper tap water sample if at least one of the following conditions is met:
	●	The laboratory establishes that improper sample analysis caused erroneous results.
	●	The department determines that the sample was taken from a site that did not meet the site selection criteria of 567—41.4(455B).
	●	The sample container was damaged in transit to the laboratory.
	●	There is a substantial reason to believe that the sample was subject to tampering.
	●	The sample is not representative of water that would be consumed from the tap.
	●	The department determined that a major disruption of the water flow occurred in the system or building plumbing prior to sample collection, which resulted in lead or copper levels that were not representative of the system.
2. The system must report the results of all samples to the department and all supporting documentation for samples the system believes should be invalidated.
	3.	To invalidate a sample under 41.4(1)“c”(6)“1,” the decision and the rationale for the decision must be documented in writing. The department may not invalidate a sample solely on the grounds that a follow-up sample result is higher or lower than that of the original sample.
	4.	The system must collect replacement samples for any samples invalidated under subparagraph 41.4(1)“c”(6) if, after the invalidation of one or more samples, the system has too few samples to meet the minimum requirements of 41.4(1)“c”(3). Any such replacement samples must be taken as soon as possible, but no later than 20 days after the date the department invalidates the sample, or by the end of the applicable monitoring period, whichever occurs later. Replacement samples taken after the end of the applicable monitoring period shall not also be used to meet the monitoring requirements of a subsequent monitoring period. The replacement samples shall be taken at the same locations as the invalidated samples or, if that is not possible, at locations other than those already used for sampling during the monitoring period.
	(7)	Monitoring waivers for small systems. Any small system that meets the criteria of this subparagraph may apply to the department to reduce the frequency of monitoring for lead and copper under subrule 41.4(1) to once every nine years if it meets all of the materials criteria specified in 41.4(1)“c”(7)“1” and the monitoring criteria specified in 41.4(1)“c”(7)“2.”
	1.	Materials criteria. The system must demonstrate that its distribution system and service lines and all drinking water supply plumbing, including plumbing conveying drinking water within all residences and buildings connected to the system, are free of lead-containing materials and copper-containing materials, as defined below:
	●	Lead. The water system must provide certification and supporting documentation to the department that the system is free of all lead-containing materials. The system does not contain any plastic pipes which contain lead plasticizers, or plastic service lines which contain lead plasticizers. The system must be free of lead service lines, lead pipes, lead soldered pipe joints, and leaded brass or bronze alloy fittings and fixtures, unless such fittings and fixtures meet the specifications of any standard established pursuant to 42 U.S.C. 300-g-6(e).
	●	Copper. The water system must provide certification and supporting documentation to the department that the system contains no copper pipes or copper service lines.
	2.	Monitoring criteria. The system must have completed at least one six-month round of standard tap water monitoring for lead and copper at sites approved by the department and from the number of sites required by 41.4(1)“c”(3), and demonstrate that the 90th percentile levels for any and all rounds of monitoring conducted since the system became free of all lead-containing and copper-containing materials meet the following criteria:
	●	Lead levels. The system must demonstrate that the 90th percentile lead level does not exceed 0.005 mg/L.
	●	Copper levels. The system must demonstrate that the 90th percentile copper level does not exceed 0.65 mg/L.
	3.	Department approval of waiver application. The department shall notify the system of its waiver determination in writing, including the basis of its decision and any condition of the waiver. The department may require as a waiver condition that the system conduct specific activities, such as limited monitoring and periodic outreach to customers to remind them to avoid installation of materials that would void the waiver. The system must continue monitoring for lead and copper at the tap as required by 41.4(1)“c”(4)“1” through “4,” as appropriate, until the system receives written approval for the waiver from the department.
	4.	Monitoring frequency of systems with waivers.
	●	A system must conduct tap water monitoring for lead and copper in accordance with 41.4(1)“c”(4)“4” at the reduced number of sampling sites identified in subparagraph 41.4(1)“c”(3) at least once every nine years and provide the materials certification specified in 41.4(1)“c”(7)“1” for both lead and copper to the department along with the monitoring results. Samples collected every nine years shall be collected no later than every ninth calendar year.
	●	A system with a waiver must notify the department in writing pursuant to 567—subparagraph 42.4(2)“a”(3) of any upcoming long-term change in treatment or addition of a new source, as described in that subparagraph. The department must review and approve the addition of a new source or long-term change in water treatment before it is implemented by the system. The department has the authority to require the system to add or modify waiver conditions, such as to require recertification that the system is free of lead-containing and copper-containing materials or to require additional monitoring, if the department deems such modifications are necessary to address treatment or source water changes at the system.
	●	If a system with a waiver becomes aware that it is no longer free of lead-containing or copper-containing materials, such as from new construction or repairs, the system shall notify the department in writing no later than 60 days after becoming aware of such a change.
	5.	Continued eligibility. If the system continues to satisfy the requirements of 41.4(1)“c”(7)“4,” the waiver will be renewed automatically, unless any of the conditions listed below occur. A system whose waiver has been revoked may reapply for a waiver at such time as it again meets the appropriate materials and monitoring criteria of 41.4(1)“c”(7)“1” and 41.4(1)“c”(7)“2.”
	●	A system no longer satisfies the materials criteria of 41.4(1)“c”(7)“1,” or has a 90th percentile lead level greater than 0.005 mg/L or a 90th percentile copper level greater than 0.65 mg/L.
	●	The department notifies the system in writing that the waiver has been revoked, including the basis of its decision.
	6.	Requirements following waiver revocation. A system whose waiver has been revoked by the department is subject to the corrosion control treatment and lead and copper tap water monitoring requirements as follows:
	●	If the system exceeds the lead or copper action level, the system must implement corrosion control treatment in accordance with the deadlines specified in 567—paragraph 43.7(1)“e,” and any other applicable parts of 567—41.4(455B).
	●	If the system meets both the lead and copper action levels, the system must monitor for lead and copper at the tap no less frequently than once every three years using the reduced number of sample sites specified in subparagraph 41.4(1)“c”(3).
	d. 	Water quality parameter monitoring requirements. All large public water supply systems (and all small and medium-size public water supply systems that exceed the lead or copper action level) shall monitor water quality parameters in addition to lead and copper in accordance with this subrule. The requirements of this subrule are summarized in the table at the end of 41.4(1)“d”(6). The water quality parameters must be reported in accordance with the monthly operation report requirements listed in 567—subrule 42.4(3).
	(1)	General requirements.
	1.	Sample collection methods. Tap samples shall be representative of water quality throughout the distribution system taking into account the number of persons served, the different sources of water, the different treatment methods employed by the system, and seasonal variability. Tap sampling under this subrule is not required to be conducted at taps targeted for lead and copper sampling under 41.4(1)“c”(1)“1.” Systems may conduct tap sampling for water quality parameters at sites used for coliform sampling. Samples collected at the entry point(s) to the distribution system shall be from locations representative of each source after treatment. If a system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating conditions (i.e., when water is representative of all sources being used).
	2.	Number of samples.
	●	Systems shall collect two tap samples for applicable water quality parameters during each monitoring period specified in 41.4(1)“d”(2) through (5) from the following number of sites.
REQUIRED NUMBER OF SAMPLES: WATER QUALITY PARAMETERS

System Size (Number of People Served)	Number of Sites for Water Quality Parameters	
greater than 100,000	25	
10,001 to 100,000	10	
3,301 to 10,000	3	
501 to 3,300	2	
101 to 500	1	
less than or equal to 100	1	
	●	Except as provided in 41.4(1)“d”(3)“3,” systems shall collect two samples for each applicable water quality parameter at each entry point to the distribution system during each six-month monitoring period specified in 41.4(1)“d”(2). During each monitoring period specified in 41.4(1)“d”(2). During each monitoring period specified in 41.4(1)“d”(3) through (5), systems shall collect one sample for each applicable water quality parameter at each entry point to the distribution system.
	(2)	Initial sampling. Large water systems shall measure the applicable water quality parameters as specified below at taps and at each entry point to the distribution system during each six-month monitoring period specified in 41.4(1)“c”(4)“1.” Small and medium-size systems shall measure the applicable water quality parameters at taps and at each entry point to the distribution system during each six-month monitoring period specified in 41.4(1)“c”(4)“1” during which the system exceeds the lead or copper action level. Tap water and entry point monitoring shall include: pH; alkalinity; orthophosphate, when an inhibitor containing a phosphate compound is used; silica, when an inhibitor containing a silicate compound is used; calcium; conductivity; and water temperature.
	(3)	Monitoring after installation of corrosion control. Large systems which install optimal corrosion control treatment pursuant to 567—subparagraph 43.7(1)“d”(4) shall measure the water quality parameters at the locations and frequencies specified below during each six-month monitoring period specified in 41.4(1)“c”(4)“2.” Small or medium-size systems which install optimal corrosion control treatment shall conduct such monitoring during each six-month monitoring period specified in 41.4(1)“c”(4)“2” in which the system exceeds the lead or copper action level.
	1.	Tap water monitoring shall include two samples for: pH; alkalinity; orthophosphate, when an inhibitor containing a phosphate compound is used; silica, when an inhibitor containing a silicate compound is used; calcium, when calcium carbonate stabilization is used as part of corrosion control.
	2.	Except as provided for in 41.4(1)“d”(3)“3,” monitoring at each entry point to the distribution system shall include one sample every two weeks (biweekly) for: pH; a reading of the dosage rate of the chemical used to adjust alkalinity, and the alkalinity concentration when alkalinity is adjusted as part of optimal corrosion control; and a reading of the dosage rate of the inhibitor used, and the concentration of orthophosphate or silica (whichever is applicable) when a corrosion inhibitor is used as part of optimal corrosion control.
	3.	Any groundwater system can limit entry point sampling described in 41.4(1)“d”(3)“3” to those entry points that are representative of water quality and treatment conditions throughout the system. If water from untreated groundwater sources mixes with water from treated groundwater sources, the system must monitor for water quality parameters both at representative entry points receiving treatment and representative entry points receiving no treatment. Prior to the start of any monitoring under this paragraph, the system shall provide to the department written information identifying the selected entry points and documentation sufficient to demonstrate that the sites are representative of water quality and treatment conditions throughout the system, including information on seasonal variability.
	(4)	Monitoring after the department specifies water quality parameter values for optimal corrosion control. After the department specifies the values for applicable water quality control parameters reflecting optimal corrosion control treatment, all large systems shall measure the applicable water quality parameters according to 41.4(1)“d”(3) and determine compliance with the requirements of 567—paragraph 43.7(2)“g” every six months, with the first six-month period to begin on either January 1 or July 1, whichever comes first, after the department specifies the optimal values under 567—paragraph 43.7(2)“f.” Any small or medium-size system shall conduct such monitoring during each monitoring period specified in 41.4(1)“c”(4)“3” in which the system exceeds the lead or copper action level. For any such small and medium-size system that is subject to a reduced monitoring frequency pursuant to 41.4(1)“c”(4)“4” at the time of the action level exceedance, the start of the applicable six-month monitoring period under this paragraph shall coincide with the end of the applicable monitoring period under 41.4(1)“c”(4)“4.” Compliance with department-designated optimal water quality parameter values shall be determined as specified in 567—paragraph 43.7(2)“g.”
	(5)	Reduced monitoring.
	1.	Public water supply systems that maintain the range of values for the water quality parameters reflecting optimal corrosion control treatment during each of two consecutive six-month monitoring periods under 41.4(1)“c”(4) shall continue monitoring at the entry point(s) to the distribution system as specified in 567—paragraph 43.7(2)“f.” Such system may collect two tap samples for applicable water quality parameters from the following reduced number of sites during each six-month monitoring period.
REDUCED WATER QUALITY PARAMETER MONITORING

System Size
(Number of People Served)	Reduced Number of Sites for
Water Quality Parameters	
greater than 100,000	10	
10,001 to 100,000	7	
3,301 to 10,000	3	
501 to 3,300	2	
101 to 500	1	
less than or equal to 100	1	
	2.	A public water system that maintains the range of values for the water quality parameters reflecting optimal corrosion control treatment specified by the department under 567—paragraph 43.7(2)“f” during three consecutive years of monitoring may reduce the frequency with which the system collects the number of tap samples for applicable water quality parameters specified in 41.4(1)“d”(5) from every six months to annually. This sampling shall begin during the calendar year immediately following the end of the monitoring period in which the third consecutive year of six-month monitoring occurs. Any system that maintains the range of values for the water quality parameters reflecting optimal corrosion control treatment specified by the department under 567—paragraph 43.7(2)“f” during three consecutive years of annual monitoring may reduce the frequency with which it collects the number of tap samples for applicable water quality parameters specified in 41.4(1)“d”(5) from annually to every three years. This sampling shall begin no later than the third calendar year following the end of the monitoring period in which the third consecutive year of monitoring occurs.
A water system may reduce the frequency with which it collects tap samples for applicable water quality parameters specified in 41.4(1)“d”(5)“1” to every three years if it demonstrates during two consecutive monitoring periods that its tap water lead level at the 90th percentile is less than or equal to 0.005 mg/L, that its tap water copper level at the 90th percentile is less than or equal to 0.65 mg/L, and that it also has maintained the range of values for the water quality parameters reflecting optimal corrosion control treatment specified by the department under 567—paragraph 43.7(2)“f.” Monitoring conducted every three years shall be done no later than every third calendar year.
	3.	A public water system that conducts sampling annually shall collect these samples evenly throughout the year so as to reflect seasonal variability.
	4.	Any water system subject to the reduced monitoring frequency that fails to operate at or above the minimum value or within the range of values for the water quality parameters specified by the department under 567—paragraph 43.7(2)“f” for more than nine days in any six-month period specified in 567—paragraph 43.7(2)“g” shall resume distribution system tap water sampling in accordance with the number and frequency requirements in 41.4(1)“d”(3). Such a system may resume annual monitoring for water quality parameters at the tap at the reduced number of sites specified in 41.4(1)“d”(5)“1” after it has completed two subsequent consecutive six-month rounds of monitoring that meet the criteria of that paragraph or may resume triennial monitoring for water quality parameters at the tap at the reduced number of sites after it demonstrates through subsequent rounds of monitoring that it meets the criteria in 41.4(1)“d”(5)“2.”
	(6)	Additional monitoring by systems. The results of any monitoring conducted in addition to the minimum requirements of this subrule shall be considered in making any determinations (i.e., determining concentrations of water quality parameters) under this subrule or 567—subrule 43.7(2).
SUMMARY OF MONITORING REQUIREMENTS FOR WATER QUALITY PARAMETERS1

Monitoring Period	Location	Parameters2	Frequency	
Initial Monitoring	Taps and at entry point(s) to distribution systems	pH, alkalinity, orthophosphate or silica3, calcium, conductivity, temperature	Every 6 months	
After Installation of Corrosion Control	Taps	pH, alkalinity, orthophosphate or silica3, calcium4	Every 6 months	
	Entry point(s) to distribution system6	pH, alkalinity, if alkalinity is adjusted as part of corrosion control then include the chemical additive dosage rate and concentration, inhibitor dosage rate and inhibitor residual5	At least every two weeks	
After Department Specifies Parameter Values for Optimal Corrosion Control	Taps	pH, alkalinity, orthophosphate or silica3, calcium4	Every 6 months	
	Entry point(s) to distribution system6	pH, alkalinity, if alkalinity is adjusted as part of corrosion control then include the chemical additive dosage rate and concentration, inhibitor dosage rate and inhibitor residual5	At least every two weeks	
Reduced Monitoring	Taps	pH, alkalinity, orthophosphate or silica3, calcium4	Every 6 months, annually7, or every 3 years8, at a reduced number of sites	
	Entry point(s) to distribution system6	pH, alkalinity, if alkalinity is adjusted as part of corrosion control then include the chemical additive dosage rate and concentration, inhibitor dosage rate and inhibitor residual5	At least every two weeks	
1Table is for illustrative purposes; consult the text of this subrule for precise regulatory requirements.
2Small and medium-size systems have to monitor for water quality parameters only during monitoring periods in which the system exceeds the lead or copper action level.
3Orthophosphate must be measured only when an inhibitor containing a phosphate compound is used. Silica must be measured only when an inhibitor containing silicate compound is used.
4Calcium must be measured only when calcium carbonate stabilization is used as part of corrosion control.
5Inhibitor dosage rates and inhibitor residual concentrations (orthophosphate or silica) must be measured only when an inhibitor is used.
6Groundwater systems may limit monitoring to representative locations throughout the systems.
7Water systems may reduce frequency of monitoring for water quality parameters at the tap from every six months to annually if they have maintained the range of values for water quality parameters reflecting optimal corrosion control during three consecutive years of monitoring.
8Water systems may further reduce the frequency of monitoring for water quality parameters at the tap from annually to once every three years if they have maintained the range of values for water quality parameters reflecting optimal corrosion control during three consecutive years of annual monitoring. Water systems may accelerate to triennial monitoring for water quality parameters at the tap if they have maintained 90th percentile lead levels less than or equal to 0.005 mg/L, 90th percentile copper levels less than or equal to 0.65mg/L, and the range of water quality parameters designated by the department under 567—paragraph 43.7(2)“f” as representing optimal corrosion control during two consecutive six-month monitoring periods.
	e. 	Lead and copper source water monitoring requirements.
	(1)	Sample location, collection methods, and number of samples.
	1.	A water system that fails to meet the lead or copper action level on the basis of tap samples collected in accordance with 41.4(1)“c” shall collect lead and copper source water samples in accordance with the following requirements regarding sample location, number of samples, and collection methods:
	●	Groundwater systems shall take a minimum of one sample at every entry point to the distribution system (source entry point) which is representative of each well after treatment. The system shall take one sample at the same source entry point unless conditions make another sampling location more representative of each source or treatment plant.
	●	Surface water systems and any system with a combination of surface water and groundwater shall take a minimum of one sample at every entry point to the distribution system after any application of treatment or in the distribution system at a point which is representative of each source after treatment. The system shall take each sample at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.
	●	If a system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating conditions, when water is representative of all sources being used.
	2.	Where the results of sampling indicate an exceedance of maximum permissible source water levels established under 567—subparagraph 43.7(3)“b”(4), the department may require that one additional sample be collected as soon as possible after the initial sample was taken (but not to exceed two weeks) at the same sampling point. If a confirmation sample is taken for lead or copper, then the results of the initial and confirmation samples shall be averaged in determining compliance with the maximum permissible levels. Lead and copper analytical results below the detection limit shall be considered to be zero. Analytical results above the detection limit but below the practical quantification level (PQL) shall either be considered as the measured value or be considered one-half the PQL.
	(2)	Monitoring after system exceeds tap water action level. Any system which exceeds the lead or copper action level at the tap shall collect one source water sample from each entry point to the distribution system no later than six months after the end of the monitoring period during which the lead or copper action level was exceeded. For monitoring periods that are annual or less frequent, the end of the monitoring period is September 30 of the calendar year in which the sampling occurs or, if the department has established an alternate monitoring period, the last day of that period.
	(3)	Monitoring after installation of source water treatment. Any system which installs source water treatment pursuant to 567—subparagraph 43.7(3)“a”(3) shall collect an additional source water sample from each entry point to the distribution system during two consecutive six-month monitoring periods by the deadline specified.
	(4)	Monitoring frequency after the department specifies maximum permissible source water levels or determines that source water treatment is not needed.
	1.	A system shall monitor at the frequency specified below in cases where the department specifies maximum permissible source water levels under 567—subparagraph 43.7(3)“b”(4) or determines that the system is not required to install source water treatment under 567—subparagraph 43.7(3)“b”(2). A water system using only groundwater shall collect samples once during the three-year compliance period in effect when the department makes this determination. Such systems shall collect samples once during each subsequent compliance period. Triennial samples shall be collected every third calendar year. A public water system using surface water (or a combination of surface and groundwater) shall collect samples once during each year, the first annual monitoring period to begin during the year in which the department determination is made under this subparagraph.
	2.	A system using only groundwater is not required to conduct source water sampling for lead or copper if the system meets the action level for the specific contaminant in tap water samples during the entire source water sampling.
	(5)	Reduced monitoring frequency.
	1.	A water system using only groundwater may reduce the monitoring frequency for lead and copper in source water to once during each nine-year compliance cycle provided that the samples are collected no later than every ninth calendar year and if the system meets one of the following criteria:
	●	The system demonstrates that finished drinking water entering the distribution system has been maintained below the maximum permissible lead or copper concentrations specified by the department in 567—subparagraph 43.7(3)“b”(4) during at least three consecutive compliance periods under 41.4(1)“e”(4)“1”; or
	●	The department has determined that source water treatment is not needed and the system demonstrates that, during at least three consecutive compliance periods in which sampling was conducted under 41.4(1)“e”(4)“1,” the concentration of lead in source water was less than or equal to 0.005 mg/L and the concentration of copper in source water was less than or equal to 0.65 mg/L.
	2.	A water system using surface water (or a combination of surface water and groundwater) may reduce the monitoring frequency in 41.4(1)“e”(4)“1” to once during each nine-year compliance cycle provided that the samples are collected no later than every ninth calendar year and if that system meets one of the following criteria:
	●	The system demonstrates that finished drinking water entering the distribution system has been maintained below the maximum permissible lead and copper concentrations specified by the department in 567—subparagraph 43.7(3)“b”(4) for at least three consecutive years; or
	●	The department has determined that source water treatment is not needed and the system demonstrates that, during at least three consecutive years, the concentration of lead in source water was less than or equal to 0.005 mg/L and the concentration of copper in source water was less than or equal to 0.65 mg/L.
	3.	A water system that uses a new source of water is not eligible for reduced monitoring for lead or copper until concentrations in samples collected from the new source during three consecutive monitoring periods are below the maximum permissible lead and copper concentrations specified.
	f. 	Corrosivity monitoring protocol — special monitoring for corrosivity characteristics. Suppliers of water for community public water systems shall collect samples from a representative entry point to the water distribution system for the purpose of analysis to determine the corrosivity characteristics of the water. The determination of corrosivity characteristics of water shall only include one round of sampling, except in cases where the department concludes additional monitoring is necessary due to variability of the raw water sources. Sampling requirements and approved analytical methods are as follows:
	(1)	Surface water systems. Systems utilizing a surface water source either in whole or in part shall collect two samples per plant for the purpose of determining the corrosivity characteristics. One of these samples is to be collected during the midwinter months and the other during midsummer.
	(2)	Groundwater systems. Systems utilizing groundwater sources shall collect one sample per plant or source, except systems with multiple plants that do not alter the corrosivity characteristics identified in 41.4(1)“f”(3) or systems served by multiple wells drawing raw water from a single aquifer may, with departmental approval, be considered one treatment plant or source when determining the number of samples required.
	(3)	Corrosivity characteristics analytical parameters. Determination of corrosivity characteristics of water shall include measurements of pH, calcium hardness, alkalinity, temperature, total dissolved solids (total filterable residue), and calculation of the Langelier Index. In addition, sulfate and chloride monitoring may be required by the department. At the department’s discretion, the Aggressiveness Index test may be substituted for the Langelier Index test.
	(4)	Corrosivity indices methodology. The following methods must be used to calculate the corrosivity indices:
	1.	Aggressiveness Index—“ANSI/AWWA C401-93: AWWA Standard for the Selection of Asbestos Cement Pressure Pipe, 4″–16″ for Water Distribution Systems,” American Water Works Association, Denver, CO.
	2.	Langelier Index—“Standard Methods for the Examination of Water and Wastewater,” 14th edition, American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710, (1975), Method 203, pp.	61-63.
	(5)	Distribution system construction materials. Community and nontransient noncommunity water supply systems shall identify whether the following construction materials are present in their distribution system and report to the department:
	1.	Lead from piping, solder, caulking, interior lining of distribution mains, alloys, and home plumbing.
	2.	Copper from piping and alloys, service lines, and home plumbing.
	3.	Galvanized piping, service lines, and home plumbing.
	4.	Ferrous piping materials such as cast iron and steel.
	5.	Asbestos cement pipe.
	6.	Vinyl lined asbestos cement pipe.
	7.	Coal tar lined pipes and tanks.
	8.	Pipe with asbestos cement lining.
	g. 	Lead, copper, and water quality parameter analytical methods.
	(1)	Analytical methods. Analyses for alkalinity, calcium, conductivity, orthophosphate, pH, silica, and temperature may be performed by a Grade I, II, III, or IV certified operator meeting the requirements of 567—Chapter 81, any person under the supervision of a Grade I, II, III, or IV certified operator meeting the requirements of 567—Chapter 81, or a laboratory certified by the department to perform analysis under 567—Chapter 83. Analyses under this subrule for lead and copper shall only be conducted by laboratories that have been certified by the department, pursuant to 567—Chapter 83. The following methods must be used:
LEAD, COPPER AND WATER QUALITY PARAMETER ANALYTICAL METHODS

Contaminant	Methodology9	Reference (Method Number)	
		EPA	ASTM3	SM	SM Online16	USGS5 or Other	
Alkalinity	Titrimetric	 	D1067-92B, 02B, 06B,
11B	2320 B11, 15, 18	2320 B-97	 	
 	Electrometric titration	 	 	 	 	I-1030-85	
Calcium	EDTA titrimetric	 	D511-93A, 03A, 09A, 14A	3500-Ca D4	3500-Ca B-97	 	
 	 	 	 	3500-Ca
B12, 15, 18	3500-Ca B-97	 	
 	Atomic absorption; direct aspiration	 	D511-93B, 03B, 09B, 14B	3111 B4, 15, 18	3111 B-99	 	
 	Inductively coupled plasma	200.72	 	3120 B11, 15, 18	3120 B-99	 	
 	Ion chromatography	 	D6919-03, 09	 	 	 	
 	Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)	200.5, Rev.	4.217	 	 	 	 	
Chloride	Ion chromatography	300.08, 300.113	D4327-97, 03	4110 B11, 15	4550 B-00	 	
 	Potentiometric titration	 	 	4500-Cl-
D11, 15	4500-Cl-
D-97	 	
 	Argentometric titration	 	D512-89B (reapproved 1999), D512-04B	4500-Cl-
B11, 15	4500-Cl-
B-97	 	
 	Capillary ion electrophoresis	 	 	 	 	D6508, Rev.	214	
Conductivity	Conductance	 	D1125-95A
(reapproved 1999), 14A	2510 B11, 15, 18	2510 B-97	 	
Copper6	Atomic absorption; furnace technique	 	D1688-95C, 02C, 07C, 12C	3113 B4, 15, 18	3113 B-99, 04, 10	 	
 	Atomic absorption; direct aspiration	 	D1688-95A, 02A, 07A, 12A	3111 B4, 15, 18	3111 B-99	 	
 	Inductively coupled plasma	200.72	 	3120 B11, 15, 18	3120 B-99	 	
 	Inductively coupled plasma; mass spectrometry	200.82	 	 	 	 	
 	Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)	200.5, Rev.	4.217	 	 	 	 	
 	Atomic absorption; platform furnace	200.92	 	 	 	 	
 	Colorimetric	 	 	 	 	Hach Method 802619; Hach Method 1027220	
Lead6	Atomic absorption;
furnace technique	 	D3559-96D, 03D, 08D	3113 B4, 15, 18	3113 B-99, 04, 10	 	
 	Inductively coupled plasma; mass spectrometry	200.82	 	 	 	 	
 	Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)	200.5, Rev.	4.217	 	 	 	 	
 	Atomic absorption; platform furnace technique	200.92	 	 	 	 	
 	Differential pulse anodic stripping voltammetry	 	 	 	 	Method 100110	
pH	Electrometric	150.11	D1293-95, 99, 12	4500-H+
B11, 15, 18	4500-H+ B-00	 	
 	 	150.21	 	 	 	 	
Orthophosphate (Unfiltered, no digestion or hydrolysis)	Colorimetric, automated, ascorbic acid	365.18	 	4500-P F11, 15, 18	4500-P F-99	Thermo
Fisher Discrete Analyzer21	
 	Colorimetric, ascorbic acid, single reagent	 	D515-88A	4500-P E11, 15, 18	4500-P E-99	 	
 	Colorimetric, phosphomolybdate;	 	 	 	 	I-1602-85	
 	Automated-segmented flow	 	 	 	 	I-2601-908	
 	Automated discrete	 	 	 	 	I-2598-85	
 	Ion chromatography	300.07, 300.113	D4327-97, 03, 11	4110 B11, 15, 18	4110 B-00	 	
 	Capillary ion electrophoresis	 	 	 	 	D6508, Rev.	214	
Silica	Colorimetric, molybdate blue	 	 	 	 	I-1700-85	
 	Automated-segmented flow	 	 	 	 	I-2700-85	
 	Colorimetric	 	D859-95, 00, 05, 10	 	 	 	
 	Molybdosilicate	 	 	4500-Si D4	4500-SiO2 C-97	 	
 	 	 	 	4500-SiO2 C12, 15, 18	4500-SiO2 C-97	 	
 	Heteropoly blue	 	 	4500-Si E15	4500-SiO2 D-97	 	
 	 	 	 	4500-SiO2 D12, 15, 18	4500-SiO2 D-97	 	
 	Automated method for molybdate-reactive silica	 	 	4500-Si F
4500-SiO2 E12, 15, 18	4500-SiO2 E-97	 	
 	Inductively coupled plasma6	200.72	 	3120 B11, 15, 18	3120 B-99	 	
 	Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES)	200.5, Rev.	4.217	 	 	 	 	
Sulfate	Ion chromatography	300.07, 300.113	D4327-97, 03	411011, 15, 18	4110 B-00	 	
 	Automated methylthymol blue	375.27	 	4500-SO4 F11, 15	4500-SO4-2 F-97	 	
 	Gravimetric	 	 	4500-SO4 C11, 15
4500-SO4 D11, 15	4500-SO4-2 C-97 4500-SO4-2 D-97	 	
 	Turbidimetric	 	D516-90, 02, 07	4500-SO4 E11, 15	4500-SO4-2 E-97	 	
 	Capillary ion electrophoresis	 	 	 	 	D6508, Rev.	214	
Temperature	Thermometric	 	 	2550 B11, 15, 18	2550-00, 10	 	
Total Filterable Residue (TDS)	Gravimetric	 	 	2540 C11, 15	2540 C-97	 	

<fo:wrapper font-size="8pt">The procedures shall be done in accordance with the documents listed below. The incorporation by reference of the following documents was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies of the documents may be obtained from the sources listed below. Information regarding obtaining these documents can be obtained from the Safe Drinking Water Hotline at (800)426-4791. Documents may be inspected at EPA’s Drinking Water Docket, 401 M Street, SW, Washington, DC 20460 (telephone: (202)260-3027); or at the Office of Federal Register, 800 North Capitol Street, NW, Suite 700, Washington, DC.</fo:wrapper>	
1“Methods for Chemical Analysis of Water and Wastes,” EPA-600/4-79-020, March 1983. Available at NTIS as PB84-128677.
2“Methods for the Determination of Metals in Environmental Samples,” EPA-600/4-91-010, June 1991. Available at NTIS as PB91-231498.
3Annual Book of ASTM Standards, 1994, 1996, 1999, or 2003, Vols.	11.01 and 11.02, American Society for Testing and Materials, International; the methods listed are the only versions that may be used. The previous versions of D1688-95A and D1688-95C (copper), D3559-95D (lead), D1293-95 (pH), D1125-91A (conductivity), and D859-94 (silica) are also approved. These previous versions, D1688-90A, C, D3559-90D, D1293-84, D1125-91A and D859-88, respectively, are located in the Annual Book of ASTM Standards, 1994, Volume 11.01. Copies may be obtained from ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428 or www.astm.org.
418th and 19th editions of Standard Methods for the Examination of Water and Wastewater, 1992 and 1995, respectively, American Public Health Association. Either edition may be used. Copies may be obtained from the American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710.
5Techniques of Water Resources Investigation of the U.S. Geological Survey, Book 5, Chapter A-1, 3rd ed., 1989. Available from Information Services, U.S. Geological Survey, Federal Center, Box 25286, Denver, CO 80225-0425.
6Samples may not be filtered. Samples that contain less than 1 NTU (Nephelometric turbidity unit) and are properly preserved (concentrated nitric acid to pH < 2) may be analyzed directly (without digestion) for total metals; otherwise, digestion is required. When digestion is required, the total recoverable technique as defined in the method must be used.
7“Methods for the Determination of Inorganic Substances in Environmental Samples,” EPA/600/R-93/100, August 1993. Available at NTIS as PB94-120821.
8“Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Inorganic and Organic Constituents in Water and Fluvial Sediments, Open File Report 93-125.” Available from Information Services, U.S. Geological Survey, Federal Center, Box 25286, Denver, CO 80225-0425.
9Because MDLs reported in EPA Methods 200.7 and 200.9 were determined using a 2X preconcentration step during sample digestion, MDLs determined when samples are analyzed by direct analysis (i.e., no sample digestion) will be higher. Preconcentration may be required for direct analysis of lead by Methods 200.9, 3113B, and 3559-90D unless multiple in-furnace depositions are made.
10The description for Method 1001 is available from Palintest, Ltd., 21 Kenton Lands Road, P.O. Box 18395, Erlanger, KY 41018; or from the Hach Company, P.O. Box 389, Loveland, CO 80538.
11The 18th, 19th, and 20th editions of Standard Methods for the Examination of Water and Wastewater, 1992, 1995, and 1998, respectively, American Public Health Association. Any edition may be used, except that the versions of 3111B and 3113B in the 20th edition may not be used. Copies may be obtained from the American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710.
12The 20th edition of Standard Methods for the Examination of Water and Wastewater, 1998, American Public Health Association. Copies may be obtained from the American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710.
13“Methods for the Determination of Organic and Inorganic Compounds in Drinking Water,” Vol.	1, EPA 815-R-00-014, August 2000. Available at NTIS, PB2000-106981.
14Method D6508, Rev.	2, “Test Method for Determination of Dissolved Inorganic Anions in Aqueous Matrices Using Capillary Ion Electrophoresis and Chromate Electrolyte,” available from Waters Corp., 34 Maple Street, Milford, MA 01757; telephone: (508)482-2131.
15Standard Methods for the Examination of Water and Wastewater, 21st edition (2005), American Public Health Association. Available from the American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710.
16Standard Methods Online is available at www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only online versions that may be used.
17EPA Method 200.5, Revision 4.2: “Determination of Trace Elements in Drinking Water by Axially Viewed Inductively Coupled Plasma-Atomic Emission Spectrometry,” 2003. EPA/600/R-06/115. Available at www.nemi.gov.
18Standard Methods for the Examination of Water and Wastewater, 22nd edition (2012), American Public Health Association. Available from the American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710.
19Hach Company. “Hach Method 8026 – Spectrophotometric Measurement of Copper in Finished Drinking Water,” December 2015, Revision 1.2. Available from www.hach.com.
20Hach Company. “Hach Method 10272 – Spectrophotometric Measurement of Copper in Finished Drinking Water,” December 2015, Revision 1.2. Available from www.hach.com.
21Thermo Fisher. “Thermo Fisher Scientific Drinking Water Orthophosphate Method for Thermo Scientific Gallery Discrete Analyzer,” February 2016. Revision 5. Thermo Fisher Scientific, Ratastie 2 01620 Vantaa, Finland.
	(2)	Certified laboratory requirements. Lead and copper analyses under this subrule shall only be conducted by laboratories that have been certified by the department and are in compliance with the requirements of 567—Chapter 83.
	(3)	All lead and copper levels measured between the practical quantitation limit (PQL) and method detection limit (MDL) must be either reported as measured or they can be reported as one-half the PQL specified for lead and copper in 567—paragraph 83.6(7)“a”(5)“2.” All levels below the lead and copper MDLs must be reported as zero.
	41.4(2) Lead, copper, and corrosivity regulation by the setting of an MCL. Reserved.
[ARC 3735C, IAB 4/11/18, effective 5/16/18]
567—41.5(455B) Organic chemicals.
	41.5(1) MCLs and other requirements for organic chemicals. Maximum contaminant levels for two classes of organic chemical contaminants specified in 41.5(1)“b” apply to community water systems and nontransient noncommunity water systems as specified herein. The two referenced organic chemical classes are volatile organic chemicals (VOCs) and synthetic organic chemicals (SOCs).
The requirements also contain analytical method requirements and monitoring requirements referenced in 41.5(1)“b” and “c.” Best available technology (BAT) for control of these organic contaminants is referenced in 567—paragraph 43.3(10)“a.”
	a. 	Applicability. The maximum contaminant levels for volatile and synthetic organic contaminants apply to community and nontransient noncommunity water systems. Compliance with the volatile and synthetic organic contaminant maximum contaminant level is calculated pursuant to 41.5(1)“b.”
	b. 	Maximum contaminant levels (MCLs) and analytical methodology for organic compounds. The maximum contaminant levels for organic chemicals are listed in the table in subparagraph 41.5(1)“b”(1). Analyses for the contaminants in this subrule shall be conducted using the following methods, or their equivalent as approved by EPA. For analysis of a compliance sample, a certified laboratory must be able to achieve at least the method detection limit for the specific contaminant as listed in the following table.
	(1)	Table:
ORGANIC CHEMICAL CONTAMINANTS, CODES, MCLS, ANALYTICAL METHODS,
AND DETECTION LIMITS

Contaminant	EPA Contaminant Code	MCL (mg/L)	Methodology1	Detection Limit (mg/L)	
Volatile Organic Chemicals (VOCs):	
Benzene	2990	0.005	502.2, 524.2, 524.3, 524.47	0.0005	
Carbon tetrachloride	2982	0.005	502.2, 524.2, 524.3, 524.47, 551.1	0.0005	
Chlorobenzene (mono)	2989	0.1	502.2, 524.2, 524.3, 524.47	0.0005	
1,2-Dichlorobenzene (ortho)	2968	0.6	502.2, 524.2, 524.3, 524.47	0.0005	
1,4-Dichlorobenzene (para)	2969	0.075	502.2, 524.2, 524.3, 524.47	0.0005	
1,2-Dichloroethane	2980	0.005	502.2, 524.2, 524.3, 524.47	0.0005	
1,1-Dichloroethylene	2977	0.007	502.2, 524.2, 524.3, 524.47	0.0005	
cis-1,2-Dichloroethylene	2380	0.07	502.2, 524.2, 524.3, 524.47	0.0005	
trans-1,2-Dichloroethylene	2979	0.1	502.2, 524.2, 524.3, 524.47	0.0005	
Dichloromethane	2964	0.005	502.2, 524.2, 524.3, 524.47	0.0005	
1,2-Dichloropropane	2983*	0.005	502.2, 524.2, 524.3, 524.47	0.0005	
Ethylbenzene	2992	0.7	502.2, 524.2, 524.3, 524.47	0.0005	
Styrene	2996	0.1	502.2, 524.2, 524.3, 524.47	0.0005	
Tetrachloroethylene	2987	0.005	502.2, 524.2, 524.3, 524.47, 551.1	0.0005	
Toluene	2991	1	502.2, 524.2, 524.3, 524.47	0.0005	
1,1,1-Trichloroethane	2981	0.2	502.2, 524.2, 524.3, 524.47, 551.1	0.0005	
Trichloroethylene	2984	0.005	502.2, 524.2, 524.3, 524.47, 551.1	0.0005	
1,2,4-Trichlorobenzene	2378	0.07	502.2, 524.2, 524.3, 524.47	0.0005	
1,1,2-Trichloroethane	2985	0.005	502.2, 524.2, 524.3, 524.47, 551.1	0.0005	
Vinyl chloride	2976	0.002	502.2, 524.2, 524.3, 524.47	0.0005	
Xylenes (total)	2955*	10	502.2, 524.2, 524.3, 524.47	0.0005	
Synthetic Organic Chemicals (SOCs):	
Alachlor3	2051	0.002	505, 507, 508.1, 525.2, 525.3, 551.1	0.0002	
Aldicarb	2047	0.003	531.1, 6610	0.0005	
Aldicarb sulfone	2044	0.002	531.1, 6610	0.0008	
Aldicarb sulfoxide	2043	0.004	531.1, 6610	0.0005	
Atrazine3	2050	0.003	505, 507, 508.1, 523, 525.2, 525.3, 536, 551.1, Syngenta AG-6255	0.0001	
Benzo(a)pyrene	2306	0.0002	525.2, 525.3, 550, 550.1	0.00002	
Carbofuran	2046	0.04	531.1, 531.2, 6610, 6610B, 6610 B-042	0.0009	
Chlordane3	2959	0.002	505, 508, 508.1, 525.2, 525.3	0.0002	
2,4-D6  (as acids, salts, and esters)	2105	0.07	515.1, 515.2, 515.3, 515.4, 555, D5317-93, 98 (Reapproved 2003), 6610B, 6640-B, 6640 B-01, 6640 B-06	0.0001	
Dalapon	2031	0.2	515.1, 515.3, 515.4, 552.1, 552.2, 552.3, 557, 6640, 6610B, 6640-B, 6640 B-01, 6640 B-06	0.001	
1,2-Dibromo-3-chloropropane (DBCP)	2931	0.0002	504.1, 524.3, 551.1	0.00002	
Di(2-ethylhexyl)adipate	2035	0.4	506, 525.2, 525.3	0.0006	
Di(2-ethylhexyl)phthalate	2039	0.006	506, 525.2, 525.3	0.0006	
Dinoseb6	2041	0.007	515.1, 515.2, 515.3, 515.4, 555, 6610B, 6640-B, 6640 B-01, 6640 B-06	0.0002	
Diquat	2032	0.02	549.2	0.0004	
Endothall	2033	0.1	548.1	0.009	
Endrin3	2005	0.002	505, 508, 508.1, 525.2, 525.3, 551.1	0.00001	
Ethylene dibromide (EDB)	2946	0.00005	504.1, 524.3, 551.1	0.00001	
Glyphosate	2034	0.7	547, 6651, 6651B, 6651 B-00, 6640 B-05	0.006	
Heptachlor3	2065	0.0004	505, 508, 508.1, 525.2, 525.3, 551.1	0.00004	
Heptachlor epoxide3	2067	0.0002	505, 508, 508.1, 525.2, 525.3, 551.1	0.00002	
Hexachlorobenzene3	2274	0.001	505, 508, 508.1, 525.2, 525.3, 551.1	0.0001	
Hexachlorocyclopentadiene3	2042	0.05	505, 508, 508.1, 525.2, 525.3, 551.1	0.0001	
Lindane (gamma BHC)3	2010	0.0002	505, 508, 508.1, 525.2, 525.3, 551.1	0.00002	
Methoxychlor3	2015	0.04	505, 508, 508.1, 525.2, 525.3, 551.1	0.0001	
Oxamyl	2036	0.2	531.1, 531.2, 6610, 6610B, 6610 B-042	0.002	
Pentachlorophenol	2326	0.001	515.1, 515.2, 515.3, 515.4, 525.2, 525.3, 555, D5317-93, 98 (Reapproved 2003), 6610B, 6640-B, 6640 B-01, 6640 B-06	0.00004	
Picloram3, 6	2040	0.5	515.1, 515.2, 515.3, 515.4, 555, D5317-93, 98 (Reapproved 2003), 6610B, 6640-B, 6640 B-01, 6640 B-06	0.0001	
Polychlorinated biphenyls4
(as decachlorobiphenyl)
(as Arochlors)3	2383	0.0005	508A
505, 508, 508.1, 525.2, 525.3	0.0001	
Simazine3	2037	0.004	505, 507, 508.1, 523, 525.2, 525.3, 536, 551.1	0.00007	
2,3,7,8-TCDD (dioxin)	2063	3x10-8	1613	5x10-9	
2,4,5-TP6 (Silvex)	2110	0.05	515.1, 515.2, 515.3, 515.4, 555, D5317-93, 98 (Reapproved 2003), 6610B, 6640-B, 6640 B-01, 6640 B-06	0.0002	
Toxaphene3	2020	0.003	505, 508, 508.1, 525.2, 525.3	0.001	
*As of January 1, 1999, the contaminant codes for the following compounds were changed from the Iowa Contaminant Code to the EPA Contaminant Code:

Contaminant	Iowa Contaminant Code (Old)	EPA Contaminant Code (New)	
1,2 Dichloropropane	2325	2983	
Xylenes (total)	2974	2955	
1Analyses for the contaminants in this section shall be conducted using the following EPA methods or their equivalent as approved by EPA. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be inspected at EPA’s Drinking Water Docket, EPA West, 1301 Constitution Avenue, NW, Room 3334, Washington, DC 20460 (telephone: (202)	566-2426); or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202)741-6030, or via Internet at www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
The following methods are available from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Road, Springfield, VA 22161 (telephone: (800)553-6847).
Methods for the Determination of Organic Compounds in Drinking Water, EPA-600/4-88-039, December 1988, Revised July 1991 (NTIS PB91-231480): Methods 508A and 515.1.
Methods for the Determination of Organic Compounds in Drinking Water—Supplement I, EPA-600/4-90-020, July 1990 (NTIS PB91-146027): Methods 547, 550, 550.1.
Methods for the Determination of Organic Compounds in Drinking Water—Supplement II, EPA-600/R-92-129, August 1992 (NTIS PB92-207703): Methods 548.1, 552.1, 555.
Methods for the Determination of Organic Compounds in Drinking Water—Supplement III, EPA-600/R-95-131, August 1995 (NTIS PB95-261616): Methods 502.2, 504.1, 505, 506, 507, 508, 508.1, 515.2, 524.2, 525.2, 531.1, 551.1, 552.2.
EPA Method 523, “Determination of Triazine Pesticides and Their Degradates in Drinking Water by Gas Chromatography/Mass Spectrometry (GC/MS),” 2011. EPA-815-R-11-002. Available at www.nepis.epa.gov.
EPA Method 524.3, Version 1.0. “Measurement of Purgeable Organic Compounds in Water by Capillary Column Gas Chromatography/Mass Spectrometry,” June 2009. EPA 815-B-09-009. Available at www.nemi.gov.
EPA Method 525.3, “Determination of Semivolatile Organic Chemicals in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatograph/Mass Spectrometry (GC/MS),” 2012. EPA/600/R-12-010. Available at www.nepis.epa.gov.
EPA Method 536, “Determination of Triazine Pesticides and Their Degradates in Drinking Water by Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry (LC/ESI-MS/MS),” 2007. EPA/815-B-07-002. Available at www.nepis.epa.gov.
EPA Method 557, “Determination of Haloacetic Acids, Bromate, and Dalapon in Drinking Water by Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC-ESI-MS/MS),” September 2009. EPA 815-B-09-012. Available at www.nemi.gov.
Method 1613 “Tetra-through Octa-Chlorinated Dioxins and Furans by Isotope-Dilution HRGC/HRMS,” EPA-821-B-94-005, October 1994 (NTIS PB95-104774).
The following American Public Health Association (APHA) documents are available from APHA, 800 I Street, NW, Washington, DC 20001-3710.
Supplement to the 18th Edition of Standard Methods for the Examination of Water and Wastewater, 1994, Standard Methods for the Examination of Water and Wastewater, 19th edition, 1995, 20th edition, 1998, 21st edition, 2005, or 22nd edition, 2012 (any of these editions may be used), APHA: Method 6610 and (carbofuran and oxamyl only) 6610B and 6610 B-04; Method 6640B (21st and 22nd editions only) and SM online 6640 B-01 for 2,4-D, 2,4,5-TP Silvex, dalapon, dinoseb, pentachlorophenol, and picloram; Method 6651B (21st and 22nd editions only) and SM online 6670-B-00 for glyphosate.
Standard Methods for the Examination of Water and Wastewater, 18th edition, 1992, 19th edition, 1995, or 20th edition, 1998, (any of these editions may be used), APHA: Method 6651.
The following American Society for Testing and Materials (ASTM) method is available from ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428.
Annual book of ASTM Standards, 1999, Vol. 11.02 (or any edition published after 1993), ASTM: D5317-93, 98 (Reapproved 2003).
Methods 515.3 and 549.2 are available from U.S. EPA NERL, 26 W. Martin Luther King Drive, Cincinnati, OH 45268.
Method 515.4, “Determination of Chlorinated Acids in Drinking Water by Liquid-Liquid Microextraction, Derivatization and Fast Gas Chromatography with Electron Capture Detection,” Revision 1.0, April 2000, EPA 815/B-00/001 and EPA Method 552.3, “Determination of Haloacetic Acids and Dalapon in Drinking Water by Liquid-liquid Microextraction, Derivatization, and Gas Chromatography with Electron Capture Detection,” Revision 1.0, July 2003, EPA 815-B-03-002, available at www.epa.gov/safewater/methods/sourcalt.html.
Method 531.2, “Measurement of n-Methylcarbamoyloximes and n-Methylcarbamates in Water by Direct Aqueous Injection HPLC with Postcolumn Derivatization,” Revision 1.0, September 2001, EPA 815/B-01/002, available at www.epa.gov/safewater/methods/sourcalt.html.
Syngenta AG-625 Method, “Atrazine in Drinking Water by Immunoassay,” February 2001, is available from Syngenta Crop Protection, Inc., 410 Swing Road, P.O. Box 18300, Greensboro, NC 27419, telephone (336)632-6000.
Other required analytical test procedures germane to the conduct of these analyses are contained in Technical Notes on Drinking Water Methods, EPA-600/R-94-173, October 1994 (NTIS PB95-104766).
2Standard Methods Online is available at www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only online versions that may be used.
3Substitution of the detector specified in Method 505, 507, 508, or 508.1 for the purpose of achieving lower detection limits is allowed as follows. Either an electron capture or nitrogen-phosphorus detector may be used provided all regulatory requirements and quality control criteria are met.
4PCBs are qualitatively identified as Aroclors and measured for compliance purposes as decachlorobiphenyl. Users of Method 505 may have more difficulty in achieving the required detection limits than users of Method 508. 508.1, or 525.2.
5This method may not be used for the analysis of atrazine in any system where chlorine dioxide is used in the drinking water treatment. In samples from all other systems, any result for atrazine generated by Method AG-625 that is greater than one-half the MCL (i.e., greater than 0.0015 mg/L) must be confirmed using another approved method for this contaminant and should use additional volume of the original sample collected for compliance monitoring. In instances where a result from Method AG-625 triggers such confirmatory testing, the confirmatory result is to be used to determine compliance.
6Accurate determination of the chlorinated esters requires hydrolysis of the sample as described in EPA Methods 515.1, 515.2, 515.3, 515.4, and 555, and ASTM Method D5317-93, 98 (Reapproved 2003).
7EPA Method 524.4, Version 1.0. “Measurement of Purgeable Organic Compounds in Water by Gas Chromatography/Mass Spectrometry Using Nitrogen Purge Gas,” May 2013, EPA 815-R-13-002.
	(2)	Organic chemical compliance calculations. Compliance with 41.5(1)“b”(1) shall be determined based on the analytical results obtained at each sampling point. If one sampling point is in violation of an MCL listed in 41.5(1)“b”(1), the system is in violation of the MCL. If a system fails to collect the required number of samples, compliance will be based on the total number of samples collected. If a sample result is less than the detection limit, zero will be used when calculating the running annual average. If the system is in violation of an MCL, the water supplier is required to give notice to the department in accordance with 567—subrule 42.4(1) and to notify the public as required by 567—42.1(455B).
	1.	Systems monitoring more than once per year for VOC or SOC contaminants. For systems which monitor more than once per year, compliance with the MCL is determined by a running annual average of all samples collected at each sampling point.
	2.	Systems monitoring annually or less frequently for VOC contaminants. Systems which monitor annually or less frequently and whose VOC sample result exceeds the MCL must begin quarterly sampling. The system will not be considered in violation of the MCL until it has completed one year of quarterly sampling. However, if any sample result will cause the running annual average to exceed the MCL at any sampling point, the system is immediately out of compliance with the MCL.
	3.	Systems monitoring annually or less frequently for SOC contaminants. Systems which monitor annually or less frequently and whose SOC sample result exceeds the regulatory detection limit specified in subparagraph 41.5(1)“b”(1) must begin quarterly sampling. The system will not be considered in violation of the MCL until it has completed one year of quarterly sampling. However, if any sample result will cause the running annual average to exceed the MCL at any sampling point, the system is immediately out of compliance with the MCL.
	(3)	Treatment techniques for acrylamide and epichlorohydrin. Each public water supply system must certify annually in writing to the department (using third-party or manufacturer’s certification) that when acrylamide and epichlorohydrin are used in drinking water systems, the combination (or product) of dose and monomer level does not exceed the levels specified as follows:
Acrylamide = 0.05% dosed at 1 ppm (or equivalent)
Epichlorohydrin = 0.01% dosed at 20 ppm (or equivalent)
Certifications can rely on information provided by manufacturers or third parties, as approved by the department.
	c. 	Organic chemical monitoring requirements. Each public water system shall monitor at the time designated within each compliance period. All new systems or systems that use a new source of water must demonstrate compliance with the MCLs within the time period specified by the department. The system must also comply with the initial sampling frequencies specified by the department to ensure the system can demonstrate compliance with the MCLs. A source of water that is determined by the department to be a new source/entry point is considered to be a new source for the purposes of paragraph 41.5(1)“c.” Routine and increased monitoring frequencies shall be conducted in accordance with the requirements in this paragraph.
	(1)	Routine volatile organic chemical (VOC) monitoring requirements. Beginning on January 1, 1993, community water supplies and NTNC water supplies shall conduct monitoring of the contaminants listed in 41.5(1)“b”(1) for the purpose of determining compliance with the maximum contaminant level.
	(2)	VOC monitoring protocol.
	1.	VOC groundwater monitoring protocol. Groundwater systems shall take a minimum of one sample at every entry point to the distribution system which is representative of each well after treatment (hereafter called a source/entry point). Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source, treatment plant, or within the distribution system.
	2.	VOC surface water monitoring protocol. Surface water systems (and combined surface/groundwater systems) shall take a minimum of one sample at each entry point to the distribution system after treatment (hereafter called a source/entry point). Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source, treatment plant, or within the distribution system.
	3.	Multiple sources. If the system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating conditions (i.e., when water representative of all sources is being used). If a representative sample of all water sources cannot be obtained, as determined by the department, separate source/entry points with the appropriate monitoring requirements will be assigned by the department.
	4.	Initial VOCs monitoring frequency. Each community and nontransient noncommunity water system shall take four consecutive quarterly samples for each contaminant listed in 41.5(1)“b”(1) during each compliance period, beginning in the initial compliance period. If the initial monitoring for contaminants listed in 41.5(1)“b”(1) has been completed by December 31, 1992, and the system did not detect any contaminant listed in 41.5(1)“b”(1), then each groundwater and surface water system shall take one sample annually beginning with the initial compliance period.
	5.	Reduced VOC monitoring for groundwater systems. After a minimum of three years of annual sampling, the department may allow groundwater systems with no previous detection of any contaminant listed in 41.5(1)“b”(1) to take one sample during each compliance period.
	6.	VOC monitoring waivers. Each community and nontransient noncommunity groundwater system which does not detect a contaminant listed in 41.5(1)“b”(1) may apply to the department for a waiver from the requirements of 41.5(1)“c”(2)“4” and “5” after completing the initial monitoring. A waiver shall be effective for no more than six years (two compliance periods). The department may also issue waivers to small systems for the initial round of monitoring for 1,2,4-trichlorobenzene. Detection is defined as greater than or equal to 0.0005 mg/L.
	7.	Bases of a VOC monitoring waiver. The department may grant a waiver if the department finds that there has not been any knowledge of previous use (including transport, storage, or disposal) of the contaminant within the watershed or zone of influence of the system. If previous use of the contaminant is unknown or it has been used previously, then the following factors shall be used to determine whether a waiver is granted.
	●	Previous analytical results.
	●	The proximity of the system to a potential point or nonpoint source of contamination. Point sources include spills and leaks of chemicals at or near a water treatment facility or at manufacturing, distribution, or storage facilities, or from hazardous and municipal waste landfills and other waste handling or treatment facilities.
	●	The environmental persistence and transport of the contaminants.
	●	The number of persons served by the public water system and the proximity of a smaller system to a larger system, and
	●	How well the water source is protected against contamination, such as whether it is a surface or groundwater system. Groundwater systems must consider factors such as depth of the well, the type of soil, and wellhead protection. Surface water systems must consider watershed protection.
	8.	VOC monitoring waiver requirements for groundwater systems. As a condition of the waiver, a groundwater system must take one sample at each sampling point during the time the waiver is effective (i.e., one sample during two compliance periods or six years) and update its vulnerability assessment considering the factors listed in 41.5(1)“c”(2)“7.” Based on this vulnerability assessment the department must reconfirm that the system is nonvulnerable. If the department does not reconfirm within three years of the initial vulnerability determination, then the waiver is invalidated and the system is required to sample annually as specified in 41.5(1)“c”(2)“4.”
	9.	VOC monitoring waiver requirements for surface water systems. Each community and nontransient noncommunity surface water system which does not detect a contaminant listed in 41.5(1)“b”(1) may apply to the department for a waiver from the requirements of 41.5(1)“c”(2)“4” after completing the initial monitoring. Systems meeting this criterion must be determined by the department to be nonvulnerable based on a vulnerability assessment during each compliance period. Each system receiving a waiver shall sample at the frequency specified by the department (if any).
	10.	Increased VOC monitoring. If a contaminant listed in 41.5(1)“b”(1) is detected at a level exceeding 0.0005 mg/L in any sample, then:
The system must monitor quarterly at each sampling point which resulted in a detection.
The department may decrease the quarterly monitoring requirement specified in 41.5(1)“c”(2)“4” provided it has determined that the system is reliably and consistently below the maximum contaminant level. In no case shall the department make this determination unless a groundwater system takes a minimum of two quarterly samples and a surface water system takes a minimum of four quarterly samples.
If the department determines that the system is reliably and consistently below the MCL, the department may allow the system to monitor annually. Systems which monitor annually must monitor during the quarter(s) which previously yielded the highest analytical result.
Systems which have three consecutive annual samples with no detection of a contaminant may apply to the department for a waiver as specified in 41.5(1)“c”(2)“6.”
Groundwater systems which have detected one or more of the following two-carbon organic compounds: trichloroethylene, tetrachloroethylene, 1,2-dichloroethane, 1,1,1-trichloroethane, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, or 1,1-dichloroethylene shall monitor quarterly for vinyl chloride. A vinyl chloride sample shall be taken at each sampling point at which one or more of the two-carbon organic compounds was detected. If the results of the first analysis do not detect vinyl chloride, the department may reduce the quarterly monitoring frequency of vinyl chloride monitoring to one sample during each compliance period. Surface water systems are required to monitor for vinyl chloride as specified by the department.
	11.	VOCs reliably and consistently below the MCL. Systems which violate the MCL requirements of 41.5(1)“b”(1) must monitor quarterly. After a minimum of four consecutive quarterly samples which show the system is in compliance and the department determines that the system is reliably and consistently below the maximum contaminant level, the system may monitor at the frequency and times specified in 41.5(1)“c”(2)“10,” third unnumbered paragraph (following approval by the department).
	(3)	Routine and repeat synthetic organic chemical (SOC) monitoring requirements. Analysis of the synthetic organic contaminants listed in 41.5(1)“b”(1) for the purposes of determining compliance with the maximum contaminant level shall be conducted as follows:
	1.	SOC groundwater monitoring protocols. Groundwater systems shall take a minimum of one sample at every entry point to the distribution system which is representative of each well after treatment (hereafter called a source/entry point). Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.
	2.	SOC surface water monitoring protocols. Surface water systems shall take a minimum of one sample at each entry point to the distribution system after treatment (hereafter called a source/entry point). Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant. For purposes of this paragraph, surface water systems include systems with a combination of surface and ground sources.
	3.	Multiple sources. If the system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating conditions (i.e., when water representative of all sources is being used). If a representative sample of all water sources cannot be obtained, as determined by the department, separate source/entry points with the appropriate monitoring requirements will be assigned by the department.
	4.	SOC monitoring frequency. Community and nontransient noncommunity water systems shall take four consecutive quarterly samples for each contaminant listed in 41.5(1)“b”(1) during each compliance period beginning with the compliance period starting January 1, 1993. Systems serving more than 3,300 persons which do not detect a contaminant in the initial compliance period may reduce the sampling frequency to a minimum of two quarterly samples in one year during each repeat compliance period. Systems serving less than or equal to 3,300 persons which do not detect a contaminant in the initial compliance period may reduce the sampling frequency to a minimum of one sample during each repeat compliance period.
	5.	SOC monitoring waivers. Each community and nontransient water system may apply to the department for a waiver from the requirements of 41.5(1)“c”(3)“4.” A system must reapply for a waiver for each compliance period.
	6.	Bases of an SOC monitoring waiver. The department may grant a waiver if the department finds that there has been no knowledge of previous use (including transport, storage, or disposal) of the contaminant within the watershed or zone of influence of the system. If previous use of the contaminant is unknown or it has been used previously, then the department shall determine whether a waiver may be granted by considering:
	●	Previous analytical results.
	●	The proximity of the system to a potential point or nonpoint source of contamination. Point sources include spills and leaks of chemicals at or near a water treatment facility or at manufacturing, distribution, or storage facilities, or from hazardous and municipal waste landfills and other waste handling or treatment facilities. Nonpoint sources include the use of pesticides to control insect and weed pests on agricultural areas, forest lands, home and gardens, and other land application uses.
	●	The environmental persistence and transport of the pesticide or PCBs.
	●	How well the water source is protected against contamination due to such factors as depth of the well and the type of soil and the integrity of the well casing.
	●	Elevated nitrate levels at the water supply source, and
	●	Use of PCBs in equipment used in the production, storage, or distribution of water (i.e., PCBs used in pumps and transformers).
	7.	Increased SOC monitoring. If a synthetic organic contaminant listed in 41.5(1)“b”(1) is detected in any sample, then:
	●	Each system must monitor quarterly at each sampling point which resulted in a detection.
	●	The department may decrease the quarterly SOC monitoring requirement if the system is reliably and consistently below the maximum contaminant level. In no case shall the department make this determination unless a groundwater system takes a minimum of two quarterly samples and a surface water system takes a minimum of four quarterly samples.
	●	After the department determines the system is reliably and consistently below the maximum contaminant level, the system may monitor annually. Systems which monitor annually must monitor during the quarter that previously yielded the highest analytical result.
	●	Systems which have three consecutive annual samples with no detection of a contaminant may apply to the department for a waiver as specified in 41.5(1)“c”(3)“6.”
	●	If monitoring results in detection of one or more of certain related contaminants (aldicarb, aldicarb sulfone, aldicarb sulfoxide, heptachlor, and heptachlor epoxide), then subsequent monitoring shall analyze for all related contaminants.
	8.	MCL violation and reliably/consistently below the MCL. Systems which violate the requirements of 41.5(1)“b” must monitor quarterly. After a minimum of four quarterly samples show the system is in compliance and the department determines the system is reliably and consistently below the MCL, the system shall monitor at the frequency specified in 41.5(1)“c”(3)“7.”
	(4)	Organic chemical (SOC and VOC) confirmation samples. The department may require a confirmation sample for positive or negative results. If a confirmation sample is required by the department, the result must be averaged with the first sampling result and the average is used for the compliance determination as specified by 41.5(1)“b”(2). The department has discretion to disregard results of obvious sampling errors from this calculation.
	(5)	Grandfathered organic chemical (SOC and VOC) data. The department may allow the use of monitoring data collected after January 1, 1988, for VOCs and January 1, 1990, for SOCs required under Section 1445 of the Safe Drinking Water Act for purposes of initial monitoring compliance. If the data are generally consistent with the other requirements in this subparagraph, the department may use such data (i.e., a single sample rather than four quarterly samples) to satisfy the initial monitoring requirement for the initial compliance period beginning January 1, 1993. Systems which use grandfathered samples for VOCs and did not detect any contaminants listed in 41.5(1)“b”(1) shall begin monitoring annually in accordance with 41.5(1)“c”(2) beginning January 1, 1993.
	(6)	Increased organic chemical (SOC and VOC) monitoring. The department may increase the required monitoring frequency, where necessary, to detect variations within the system (e.g., fluctuations in concentration due to seasonal use, changes in water source, changes to treatment facilities or normal operation thereof).
	(7)	Organic chemical (SOC and VOC) vulnerability assessment criteria. Vulnerability of each public water system shall be determined by the department based upon an assessment of the following factors.
	1.	VOC vulnerability assessment criteria—previous monitoring results. A system will be classified vulnerable if any sample was analyzed to contain one or more contaminants listed in 41.5(1)“b”(1)-(VOCs) or 41.5(1)“b”(3) except for trihalomethanes or other demonstrated disinfection by-products.
	2.	SOC vulnerability assessment criteria—previous monitoring results. A system will be classified vulnerable if any sample was analyzed to contain one or more contaminants listed in 41.5(1)“b”(2)-(SOCs) or 41.5(1)“b”(3) except for trihalomethanes or other demonstrated disinfection by-products.
	3.	Proximity of surface water supplies to commercial or industrial use, disposal or storage of volatile synthetic organic chemicals. Surface waters which withdraw water directly from reservoirs are considered vulnerable if the drainage basin upgradient and within two miles of the shoreline at the maximum water level contains major transportation facilities such as primary highways or railroads or any of the contaminant sources listed in this subparagraph. Surface water supplies which withdraw water directly from flowing water courses are considered vulnerable if the drainage basin upgradient and within two miles of the water intake structure contains major transportation facilities such as primary highways or railroads or any of the contaminant sources listed in this subparagraph.
	4.	Proximity of supplies to commercial or industrial use, disposal or storage of volatile synthetic organic chemicals. Wells that are not separated from sources of contamination by at least the following distances will be considered vulnerable.

Sources of Contamination	Shallow Wells as defined
in 567—40.2(455B)	Deep Wells as defined
in 567—40.2(455B)	
 	 	 	
Sanitary and industrial point discharges	400 ft	400 ft	
Mechanical waste treatment plants	400 ft	200 ft	
Lagoons	1,000 ft	400 ft	
Chemical and mineral storage (aboveground)	200 ft	l00 ft	
Chemical and mineral storage including underground storage tanks on or below ground	400 ft	200 ft	
Solid waste disposal site	1,000 ft	1,000 ft	
	5.	A system is deemed to be vulnerable for a period of three years after any positive measurement of one or more contaminants listed in 41.5(1)“b”(1) except for trihalomethanes or other demonstrated disinfection by-products.
	(8)	PCB analytical methodology. Analysis for PCBs shall be conducted using the methods in 41.5(1)“b”(1) and as follows:
	1.	Each system which monitors for PCBs shall analyze each sample using Method 505, 508, 508.1, or 525.2. Users of Method 505 may have more difficulty in achieving the required Aroclor detection limits than users of Method 508, 508.1, or 525.2.
	2.	If PCBs (as one of seven Aroclors) are detected in any sample analyzed using Method 505 or 508, the system shall reanalyze the sample using Method 508A to quantitate PCBs as decachlorobiphenyl.
PCB AROCLOR DETECTION LIMITS

Aroclor	Detection Limit (mg/L)	
1016	0.00008	
1221	0.02	
1232	0.0005	
1242	0.0003	
1248	0.0001	
1254	0.0001	
1260	0.0002	
	3.	Compliance with the PCB MCL shall be determined based upon the quantitative results of analyses using Method 508A.
	d. 	Best available technology(ies) (BATs). Rescinded IAB 8/11/99, effective 9/15/99.
	e. 	Total trihalomethanes sampling, analytical and other requirements. Rescinded IAB 1/7/04, effective 2/11/04.
	f. 	Analytical procedures—organics. Rescinded IAB 1/7/04, effective 2/11/04.
	41.5(2) Organic chemicals occurring as (nontrihalomethane) disinfection by-products. Reserved.
[ARC 9915B, IAB 12/14/11, effective 1/18/12; ARC 3735C, IAB 4/11/18, effective 5/16/18]
567—41.6(455B) Disinfection byproducts maximum contaminant levels and monitoring requirements.
	41.6(1) Stage 1 disinfection byproducts requirements.
	a. 	Applicability.
	(1)	This rule establishes criteria under which CWS and NTNC public water supply systems that add a chemical disinfectant to the water in any part of the drinking water treatment process or which provide water that contains a chemical disinfectant must modify their practices to meet the MCLs listed in this rule and the maximum residual disinfectant levels (MRDL) and treatment technique requirements for disinfection byproduct precursors listed in 567—43.6(455B).
	(2)	Rescinded IAB 1/7/04, effective 2/11/04.
	(3)	Compliance dates for this rule are based upon the source water type and the population served. Systems are required to comply with this rule as follows, unless otherwise noted. The department may assign an earlier monitoring period as part of the operation permit, but compliance with the maximum contaminant level is not required until the dates stated below.
	1.	CWS and NTNC systems which use surface water or groundwater under the direct influence of surface water in whole or in part and which serve 10,000 or more persons must comply with this rule beginning January 1, 2002.
	2.	All other CWS and NTNC systems covered by 41.6(1)“a”(1) must comply with this rule by January 1, 2004.
	(4)	Consecutive systems. Consecutive systems that provide water containing a disinfectant or oxidant are required to comply with this rule.
	(5)	Systems with multiple water sources. Systems with water sources that are used independently from each other, are not from the same source as determined by the department, or do not go through identical treatment processes are required to conduct the monitoring for the applicable disinfectants or oxidants and disinfection byproducts during operation of each source. The system must comply with this rule during the use of each water source.
	b. 	Maximum contaminant levels for disinfection byproducts.
	(1)	The maximum contaminant levels (MCLs) for disinfection byproducts are as follows:

Disinfection byproduct	MCL (mg/L)	
Bromate	0.010	
Chlorite	1.0	
Haloacetic acids (HAA5)	0.060	
Total trihalomethanes (TTHM)*	0.080	
*The TTHM MCL changed from 0.10 mg/L to 0.080 mg/L effective January 1, 2002, for CWS serving at least 10,000 people and effective January 1, 2004, for all other CWS and NTNC systems which are subject to this rule.
	(2)	Beginning on the date listed in the following table, a system must comply with the total trihalomethanes MCL and the haloacetic acid MCL as a locational running annual average at each monitoring location.

System Size (number of people served)	Date system must comply with MCL at each sampling location*	
Systems that are not part of a combined distribution system and systems that serve the largest population in the combined distribution system	
System serving at least 100,000 people	April 1, 2012	
System serving 50,000-99,999 people	October 1, 2012	
System serving 10,000-49,999 people	October 1, 2013	
System serving fewer than 10,000 people	• October 1, 2013, for all groundwater systems and for SW/IGW systems that did not collect Cryptosporidium source water samples
• October 1, 2014, for SW/IGW systems that collected Cryptosporidium source water samples	
Other systems that are part of a combined distribution system	
Consecutive or wholesale system	At the same time as the system with the earliest compliance date in the combined distribution system	
*The department may grant up to an additional 24 months for compliance with the MCLs and operational evaluation levels if the system requires capital improvements to comply with an MCL.
	c. 	Monitoring requirements for disinfection byproducts.
	(1)	General requirements.
	1.	Systems must take all samples during normal operating conditions.
	2.	Systems may consider multiple wells drawing water from a single aquifer as one treatment plant for determining the minimum number of TTHM and HAA5 samples required, with department approval.
	3.	Failure to monitor in accordance with the monitoring plan required under 41.6(1)“c”(1)“6” is a monitoring violation.
	4.	Failure to monitor is a violation for the entire period covered by the annual average where compliance is based on a running annual average of monthly or quarterly samples or averages, and the system’s failure to monitor makes it impossible to determine compliance with MCLs.
	5.	Systems may use only data collected under the provisions of this rule or 567—43.6(455B) to qualify for reduced monitoring.
	6.	Each system required to monitor under the provisions of this rule or 567—43.6(455B) must develop and implement a monitoring plan. The system must maintain the plan and make it available for inspection by the department and the general public no later than 30 days following the applicable compliance dates in 41.6(1)“a”(3). All systems using surface water or groundwater under the direct influence of surface water and serving more than 3,300 people must submit a copy of the monitoring plan to the department by the applicable date in 41.6(1)“a”(3)“1.” The department may also require the plan to be submitted by any other system. After review, the department may require changes in any plan elements. The plan must include at least the following elements:
	●	Specific locations and schedules for collecting samples for any parameters included in this rule.
	●	How the system will calculate compliance with MCLs, MRDLs, and treatment techniques.
	7.	The department may require a monthly monitoring frequency for disinfection byproducts, which would be specified in the operation permit.
	(2)	Bromate. Community and nontransient noncommunity systems using ozone for disinfection or oxidation must conduct monitoring for bromate.
	1.	Routine monitoring. Systems must take at least one sample per month for each treatment plant in the system using ozone, collected at each source/entry point to the distribution system while the ozonation system is operating under normal conditions.
	2.	Reduced monitoring. A system may reduce monitoring from monthly to quarterly, if the system’s running annual average bromate concentration is less than or equal to 0.0025 mg/L based on monthly bromate measurements for the most recent four quarters. If the system previously qualified for reduced bromate monitoring and is on quarterly sampling frequency, it may remain on reduced monitoring as long as the running annual average of the bromate samples is less than or equal to 0.0025 mg/L. If the running annual average of quarterly bromate samples exceeds 0.0025 mg/L, the system must resume routine bromate monitoring. Only three analytical methods may be used for bromate samples under reduced monitoring: EPA Method 317.0 Revision 2.0, Method 326.0, or Method 321.8.
	(3)	Chlorite. Community and nontransient noncommunity water systems using chlorine dioxide, for disinfection or oxidation, must conduct monitoring for chlorite. If the system does not use chlorine dioxide on a daily basis, the system must conduct the required daily monitoring each day chlorine dioxide is used, and any required monthly monitoring during those months in which chlorine dioxide is used during any portion of the month.
	1.	Routine daily monitoring. Systems must take daily samples at the entrance to the distribution system. For any daily sample that exceeds the chlorite MCL, the system must take additional samples in the distribution system the following day at the locations required by 41.6(1)“c”(3)“3,” which are in addition to the sample required at the entrance to the distribution system. These daily entry point to the distribution system samples may be analyzed by system personnel, in accordance with 41.6(1)“d.”
	2.	Routine monthly monitoring. Systems must take a three-sample set each month in the distribution system. The system must take one sample at each of the following locations: near the first customer, at a location representative of average residence time, and at a location reflecting maximum residence time in the distribution system. Any additional routine sampling must be conducted in the same manner (as three-sample sets, at the specified locations). The system may use the results of additional monitoring conducted in accordance with 41.6(1)“c”(3)“3” to meet the requirement for monitoring in 41.6(1)“c”(3)“2.” These monthly distribution system samples must be analyzed by a certified laboratory using an approved ion chromatography method, in accordance with 41.6(1)“d.”
	3.	Additional monitoring. On each day following a routine sample monitoring result that exceeds the chlorite MCL at the entrance to the distribution system, the system is required to take three chlorite distribution system samples at the following locations: as close to the first customer as possible, in a location representative of average residence time, and as close to the end of the distribution system as possible (reflecting maximum residence time in the distribution system). These additional distribution system samples must be analyzed by a certified laboratory using an approved ion chromatography method, in accordance with 41.6(1)“d.”
	4.	Reduced monitoring.
	●	Daily chlorite monitoring at the entrance to the distribution system required by 41.6(1)“c”(3)“1” may not be reduced.
	●	The department may allow systems with monthly chlorite monitoring in the distribution system required by 41.6(1)“c”(3)“2” to be reduced to a requirement of 1 three-sample set per quarter after one year of monitoring where no individual chlorite sample taken in the distribution system under 41.6(1)“c”(3)“2” has exceeded the chlorite MCL and the system has not been required to conduct additional monitoring under 41.6(1)“c”(3)“3.” The system may remain on the reduced monitoring schedule until either any of the three individual chlorite samples taken quarterly in the distribution system under 41.6(1)“c”(3)“2” exceeds the chlorite MCL or the system is required to conduct monitoring under 41.6(1)“c”(3)“3” of this rule, at which time the system must revert to routine monitoring.
	(4)	Total trihalomethanes (TTHM) and haloacetic acids (HAA5).
	1.	 Routine monitoring. Systems must monitor at the frequency indicated in the following table. Both the TTHM and HAA5 samples must be collected as paired samples during the same time period in order for each parameter to have the same annual average period for result comparison. A paired sample is one that is collected at the same location and time and is analyzed for both TTHM and HAA5 parameters.
Routine Monitoring Frequency for TTHM and HAA5

Type of System (source water type and population served)	Minimum Monitoring Frequency	Sample Location in the Distribution System	
SW/IGW3 system serving ≥10,000 persons	Four water samples per quarter per treatment plant	At least 25 percent of all samples collected each quarter at locations representing maximum residence time. Remaining samples taken at locations representative of at least average residence time in the distribution system and representing the entire distribution system, taking into account number of persons served, different sources of water, and different treatment methods.1	
SW/IGW3 system serving 500-9,999 persons	One water sample per quarter per treatment plant	Locations representing maximum residence time.1	
SW/IGW3 system serving <500 persons	One sample per year per treatment plant during month of warmest water temperature	Locations representing maximum residence time.1 If the sample (or average of annual samples, if more than one sample is taken) exceeds MCL, system must increase monitoring to one sample per treatment plant per quarter, taken at a point reflecting the maximum residence time in the distribution system, until system meets reduced monitoring criteria in 41.6(1)“c”(4)“2,” second bulleted paragraph.	
System using only non-IGW groundwater using chemical disinfectant and serving ≥10,000 persons	One water sample per quarter per treatment plant2	Locations representing maximum residence time.1	
System using only non-IGW groundwater using chemical disinfectant and serving <10,000 persons	One sample per year per treatment plant during month of warmest water temperature	Locations representing maximum residence time.1 If the sample (or average of annual samples, if more than one sample is taken) exceeds MCL, system must increase monitoring to one sample per treatment plant per quarter, taken at a point reflecting the maximum residence time in the distribution system, until system meets reduced monitoring criteria in 41.6(1)“c”(4)“2,” second bulleted paragraph.	
1If a system chooses to sample more frequently than the minimum required, at least 25 percent of all samples collected each quarter (including those taken in excess of the required frequency) must be taken at locations that represent the maximum residence time of the water in the distribution system. The remaining samples must be taken at locations representative of at least average residence time in the distribution system.
2Multiple wells drawing water from a single aquifer may be considered one treatment plant for determining the minimum number of samples required, with department approval.
3SW/IGW indicates those systems that use either surface water (SW) or groundwater under the direct influence of surface water (IGW), in whole or in part.
	2.	Reduced monitoring. The department may allow systems a reduced monitoring frequency, except as otherwise provided, in accordance with the following table. Source water total organic carbon (TOC) levels must be determined in accordance with 567—subparagraph 43.6(2)“c”(1).
Reduced Monitoring Frequency for TTHM and HAA5

If you are a ...	And you have monitored at least one year and your ...	You may reduce monitoring to this level	
SW/IGW1 system serving ≥10,000 persons which has a source water annual average TOC level, before any treatment, of ≤4.0 mg/L.	TTHM annual average ≤0.040 mg/L and HAA5 annual average ≤0.030 mg/L	One sample per treatment plant per quarter at distribution system location reflecting maximum residence time.	
SW/IGW1 system serving 500 - 9,999 persons that has a source water annual average TOC level, before any treatment, of ≤4.0 mg/L.	TTHM annual average ≤0.040 mg/L and HAA5 annual average ≤0.030 mg/L	One sample per treatment plant per year at distribution system location reflecting maximum residence time during month of warmest water temperature.	
SW/IGW1 system serving <500 persons	Any SW/IGW1 system serving <500 persons may not reduce its monitoring to less than one sample per treatment plant per year.	
System using only non-IGW groundwater using chemical disinfectant and serving ≥10,000 persons	TTHM annual average ≤0.040 mg/L and HAA5 annual average ≤0.030 mg/L	One sample per treatment plant per year at distribution system location reflecting maximum residence time during month of warmest water temperature.	
System using only non-IGW groundwater using chemical disinfectant and serving <10,000 persons	TTHM annual average ≤0.040 mg/L and HAA5 annual average ≤0.030 mg/L for two consecutive years;
or,
TTHM annual average ≤0.020 mg/L and HAA5 annual average ≤0.015 mg/L for one year.	One sample per treatment plant per three-year monitoring cycle at distribution system location reflecting maximum residence time during month of warmest water temperature, with the three-year cycle beginning on January 1 following quarter in which system qualifies for reduced monitoring.	
1SW/IGW indicates those systems that use either surface water (SW) or groundwater under the direct influence of surface water (IGW), in whole or in part.
	●	Systems on a reduced monitoring schedule may remain on that reduced schedule as long as the average of all samples taken in the year (for systems which must monitor quarterly) or the result of the sample (for systems which must monitor no more frequently than annually) is less than or equal to 0.060 mg/L for TTHMs and is less than or equal to 0.045 mg/L for HAA5. Systems that do not meet these levels must resume monitoring at the frequency identified in 41.6(1)“c”(4)“1” in the quarter immediately following the quarter in which the system exceeds 0.060 mg/L for TTHMs and 0.045 mg/L for HAA5. For systems using only groundwater not under the direct influence of surface water and serving fewer than 10,000 persons, if either the TTHM annual average is >0.080 mg/L or the HAA5 annual average is >0.060 mg/L, the system must go to increased monitoring identified in 41.6(1)“c”(4)“1” in the quarter immediately following the monitoring period in which the system exceeds 0.080 mg/L for TTHMs or 0.060 mg/L for HAA5.
	●	The department may allow systems on increased monitoring to return to routine monitoring if, after one year of monitoring, TTHM annual average is less than or equal to 0.060 mg/L and HAA5 annual average is less than or equal to 0.045 mg/L.
	●	The department may return a system to routine monitoring at the department’s discretion.
	d. 	Analytical requirements for disinfection byproducts.
	(1)	Systems must use only the analytical method(s) specified in this paragraph, or equivalent methods as determined by EPA, to demonstrate compliance with the requirements of this rule.
	(2)	Systems must measure disinfection byproducts by the methods (as modified by the footnotes) listed in the following table:
Approved Methods for Disinfection Byproduct Compliance Monitoring

Contaminant and Methodology	EPA Method<fo:wrapper font-size=".69em" baseline-shift=".33em">1</fo:wrapper>	Standard Method<fo:wrapper font-size=".69em" baseline-shift=".33em">2</fo:wrapper>	ASTM Method<fo:wrapper font-size=".69em" baseline-shift=".33em">3</fo:wrapper>	
TTHM	 	 	 	
	P&T/GC/EICD & PID	502.2<fo:wrapper font-size=".69em" baseline-shift=".33em">4</fo:wrapper>	 	 	
	P&T/GC/MS	524.2, 524.3, 524.4	 	 	
	LLE/GC/ECD	551.1	 	 	
HAA5	 	 	 	
	LLE (diazomethane)/GC/ECD	 	6251 B<fo:wrapper font-size=".69em" baseline-shift=".33em">5</fo:wrapper>, 6251 B-0712	 	
	SPE (acidic methanol)/GC/ECD	552.1<fo:wrapper font-size=".69em" baseline-shift=".33em">5</fo:wrapper>	 	 	
	LLE (acidic methanol)/GC/ECD	552.2, 552.3	 	 	
	Ion chromatography electrospray ionization
	tandem mass spectrometry (IC-ESI-MS/MS)	55710	 	 	
Bromate	 	 	 	
	Ion chromatography	300.1	 	D 6581-00	
	Ion chromatography & postcolumn reaction<fo:wrapper font-size=".69em" baseline-shift=".33em">9</fo:wrapper>	317.0 Rev.	2.0<fo:wrapper font-size=".69em" baseline-shift=".33em">6</fo:wrapper>, 326.0<fo:wrapper font-size=".69em" baseline-shift=".33em">6</fo:wrapper>	 	 	
	IC/ICP-MS<fo:wrapper font-size=".69em" baseline-shift=".33em">9</fo:wrapper>	321.8<fo:wrapper font-size=".69em" baseline-shift=".33em">6, 7</fo:wrapper>	 	 	
	Two-dimensional ion chromatography (IC)	302.011	 	 	
	Ion chromatography electrospray ionization
	tandem mass spectrometry (IC-ESI-MS/MS)	55710	 	 	
	Chemically suppressed ion chromatography	 	 	D 6581-08 A	
	Electrolytically suppressed ion chromatography	 	 	D 6581-08 B	
Chlorite8	 	 	 	
	Amperometric titration	 	4500-ClO<fo:wrapper font-size=".69em" baseline-shift="-.25em">2</fo:wrapper> E<fo:wrapper font-size=".69em" baseline-shift=".33em">8</fo:wrapper>	 	
	Amperometric sensor	 	 	ChlordioX Plus8, 13	
	Spectophotometry	327.0 Rev.	1.1<fo:wrapper font-size=".69em" baseline-shift=".33em">8</fo:wrapper>	 	 	
	Ion chromatography	300.0, 300.1, 317.0 Rev.	2, 326.0	 	 	
	Chemically suppressed ion chromatography	 	 	D 6581-08 A	
	Electrolytically suppressed ion chromatography	 	 	D 6581-08 B	

ECD = electron capture detector	IC = ion chromatography	P&T = purge and trap	
EICD = electrolytic conductivity detector	LLE = liquid/liquid extraction	PID = photoionization detector	
GC = gas chromatography	MS = mass spectrometer	SPE = solid phase extractor	
The procedures shall be done in accordance with the documents listed below. The incorporation by reference of the following documents was approved by the Director of the Federal Register on February 16, 1999, in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies of the documents may be obtained from the sources listed below. Information regarding obtaining these documents can be obtained from the Safe Drinking Water Hotline at (800)426-4791. Documents may be inspected at EPA’s Drinking Water Docket, 401 M Street, SW, Washington, DC 20460 (telephone: (202)260-3027); or at the Office of Federal Register, 800 North Capitol Street, NW, Suite 700, Washington, DC 20408.
1EPA: The following methods are available from the National Technical Information Service (NTIS), U.S. Department of Commerce, 5285 Port Royal Road, Springfield, VA 22161 (telephone: (800)553-6847):
Methods 300.0 and 321.8: Methods for the Determination of Organic and Inorganic Compounds in Drinking Water, Volume 1, USEPA, August 2000, EPA 815-R-00-014 (available through NTIS, PB2000-106981).
Method 300.1: “Determination of Inorganic Anions in Drinking Water by Ion Chromatography, Revision 1.0,” EPA-600/R-98/118, 1997 (available through NTIS, PB98-169196).
Method 317.0: “Determination of Inorganic Oxyhalide Disinfection By-Products in Drinking Water Using Ion Chromatography with the Addition of a Postcolumn Reagent for Trace Bromate Analysis, Revision 2.0,” USEPA, July 2001, EPA 815-B-01-001.
Method 326.0: “Determination of Inorganic Oxyhalide Disinfection By-Products in Drinking Water Using Ion Chromatography Incorporating the Addition of a Suppressor Acidified Postcolumn Reagent for Trace Bromate Analysis, Revision 1.0,” USEPA, June 2002, EPA 815-R-03-007.
Method 327.0: “Determination of Chlorine Dioxide and Chlorite Ion in Drinking Water Using Lissamine Green B and Horseradish Peroxidase with Detection by Visible Spectrophotometry, Revision 1.1,” USEPA, May 2005, EPA 815-R-05-008.
Methods 502.2, 524.2, 551.1, and 552.2: Methods for the Determination of Organic Compounds in Drinking Water—Supplement III, EPA-600/R-95-131, August 1995 (NTIS PB95-261616).
Method 524.3: “Measurement of Purgeable Organic Compounds in Water by Capillary Column Gas Chromatography/Mass Spectrometry, Version 1.0,” June 2009. EPA 815-B-09-009. Available at www.nemi.gov.
Method 524.4: “Measurement of Purgeable Organic Compounds in Water by Gas Chromatography/Mass Spectrometry Using Nitrogen Purge Gas, Version 1.0,” May 2013. EPA 815-R-13-002. Available at www.nepis.epa.gov.
Method 552.1: Methods for the Determination of Organic Compounds in Drinking Water—Supplement II, EPA-600/R-92-129, August 1992 (NTIS PB92-207703).
Method 552.3: “Determination of Haloacetic Acids and Dalapon in Drinking Water by Liquid-liquid Microextraction, Derivatization, and Gas Chromatography with Electron Capture Detection, Revision 1.0,” USEPA, July 2003, EPA-815-B-03-002.
24500-ClO2 E and 6251B: Standard Methods for the Examination of Water and Wastewater, 19th (1995), 20th (1998), 21st (2005), and 22nd (2012) editions, American Public Health Association, which are available from the American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710.
3Method D 6581-00: American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428: Annual Book of ASTM Standards, Volume 11.01, American Society for Testing and Materials, 2001 (or any year containing the cited version).
4If TTHMs are the only analytes being measured in the sample, then a PID is not required.
5The samples must be extracted within 14 days of sample collection.
6Ion chromatography and postcolumn reaction or IC/ICP-MS must be used for bromate analysis for purposes of demonstrating eligibility of reduced monitoring.
7Samples must be preserved at sample collection with 50 mg ethylenediamine (EDA)/L of sample and must be analyzed within 28 days.
8Amperometric titration or spectrophotometry may be used for routine daily monitoring of chlorite at the entrance to the distribution system, as prescribed in 41.6(1)“c”(3)“1.” Ion chromatography must be used for routine monthly monitoring of chlorite and additional monitoring of chlorite in the distribution system, as prescribed in 41.6(1)“c”(3)“2” and “3.”
9These are the only methods approved for reduced bromate monitoring under 41.6(1)“c”(2)“2.”
10EPA Method 557, “Determination of Haloacetic Acids, Bromate, and Dalapon in Drinking Water by Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC-ESI-MS/MS),” August 2009. EPA 815-B-09-012. Available at www.nemi.gov.
11EPA Method 302.0, “Determination of Bromate in Drinking Water Using Two-Dimensional Ion Chromatography with Suppressed Conductivity Detection,” September 2009. EPA 815-B-014. Available at www.nemi.gov.
12Standard Methods Online is available at www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only online versions that may be used.
13ChlordioX Plus. “Chlorine Dioxide and Chlorite in Drinking Water by Amperometry Using Disposable Sensors,” November 2013. Available from Palintest Ltd., Jamike Avenue (Suite 100), Erlanger, KY 41018.
	(3)	Certified laboratory requirements. Analyses under this rule for disinfection byproducts shall only be conducted by laboratories that have been certified by the department and are in compliance with the requirements of 567—Chapter 83, except as specified under 41.6(1)“d”(4). The performance evaluation sample acceptance limits and minimum reporting levels are listed in 567—subparagraph 83.6(7)“a”(6).
	(4)	Daily chlorite samples at the entrance to the distribution system must be measured by a Grade II, III or IV operator meeting the requirements of 567—Chapter 81, any person under the supervision of a Grade II, III or IV operator meeting the requirements of 567—Chapter 81, or a laboratory certified by the department to perform analysis under 567—Chapter 83.
	e. 	Compliance requirements for disinfection byproducts.
	(1)	General requirements.
	1.	When compliance is based on a running annual average of monthly or quarterly samples or averages and the system fails to monitor for TTHM, HAA5, or bromate, this failure to monitor will be treated as a monitoring violation for the entire period covered by the annual average.
	2.	Unless invalidated by the department, all samples taken and analyzed under the provisions of this rule must be included in determining compliance, even if that number is greater than the minimum required.
	3.	If, during the first year of monitoring under paragraph 41.6(1)“c,” any individual quarter’s average will cause the running annual average of that system to exceed the MCL, the system is out of compliance at the end of that quarter.
	(2)	Bromate. Compliance must be based on a running annual arithmetic average, computed quarterly, of monthly samples (or, for months in which the system takes more than one sample, the average of all samples taken during the month) collected by the system as prescribed by 41.6(1)“c”(2). If the average of samples covering any consecutive four-quarter period exceeds the MCL, the system is in violation of the MCL and must notify the public pursuant to 567—42.1(455B), in addition to reporting to the department pursuant to 567—paragraph 42.4(3)“d.” If a PWS fails to complete 12 consecutive months’ monitoring, compliance with the MCL for the last four-quarter compliance period must be based on an average of the available data.
	(3)	Chlorite. Compliance must be based on an arithmetic average of each three-sample set taken in the distribution system as prescribed by 41.6(1)“c”(3)“1” and 41.6(1)“c”(3)“2.” If the arithmetic average of any three-sample set exceeds the MCL, the system is in violation of the MCL and must notify the public pursuant to 567—42.1(455B), in addition to reporting to the department pursuant to 567—paragraph 42.4(3)“d.”
	(4)	TTHM and HAA5.
	1.	For systems monitoring quarterly, compliance with MCLs in 41.6(1)“b” must be based on a running annual arithmetic average, computed quarterly, of quarterly arithmetic averages of all samples collected by the system as prescribed by 41.6(1)“c”(4).
	2.	For systems monitoring less frequently than quarterly, systems demonstrate MCL compliance if the average of samples taken that year under the provisions of 41.6(1)“c”(4) does not exceed the MCLs in 41.6(1)“b.” If the average of these samples exceeds the MCL, the system must increase monitoring to once per quarter per treatment plant and is not in violation of the MCL until it has completed one year of quarterly monitoring, unless the result of fewer than four quarters of monitoring will cause the running annual average to exceed the MCL, in which case the system is in violation at the end of that quarter. Systems required to increase to quarterly monitoring must calculate compliance by including the sample that triggered the increased monitoring plus the following three quarters of monitoring.
	3.	If the running annual arithmetic average of quarterly averages covering any consecutive four-quarter period exceeds the MCL, the system is in violation of the MCL and must notify the public pursuant to 567—42.1(455B) in addition to reporting to the department pursuant to 567—paragraph 42.4(3)“d.”
	4.	If a PWS fails to complete four consecutive quarters of monitoring, compliance with the MCL for the last four-quarter compliance period must be based on an average of the available data.
	f. 	Reporting requirements for disinfection byproducts. Systems required to sample quarterly or more frequently must report to the department within ten days after the end of each quarter in which samples were collected, notwithstanding the public notification provisions of 567—42.1(455B). Systems required to sample less frequently than quarterly must report to the department within ten days after the end of each monitoring period in which samples were collected. The specific reporting requirements for disinfection byproducts are listed in 567—subparagraph 42.4(3)“d”(2).
	41.6(2) Stage 2 initial distribution system evaluation. The department is adopting by reference the requirements for the Stage 2 initial distribution system evaluation (IDSE) listed in 40 CFR 141.600-605 as adopted on January 4, 2006. This regulation establishes monitoring and other requirements for identifying compliance monitoring locations that will be used to determine compliance with maximum contaminant levels for total trihalomethanes and haloacetic acids. All CWS required to comply with 41.6(1) and all NTNC serving at least 10,000 people that are required to comply with 41.6(1) are required to comply with this subrule. The requirements in this subrule constitute national primary drinking water regulations. Only the analytical methods specified in 41.6(1)“d” may be used to demonstrate compliance with this subrule.
	41.6(3) Stage 2 disinfection byproducts requirements. The requirements of this subrule constitute national primary drinking water regulations. This subrule establishes monitoring and other requirements for achieving compliance with MCLs based on locational running annual averages (LRAA) for TTHM and HAA5.
	a. 	Applicability. All CWS and NTNC systems that use a primary or residual disinfectant other than ultraviolet light or deliver water that has been treated with a primary or residual disinfectant other than ultraviolet light must comply with the requirements in this subrule.
	(1)	Schedule. Systems must comply with the dates listed in the appropriate schedule. For the purposes of this subrule, the combined distribution system (CDS) as defined in 567—40.2(455B) only includes active connections; emergency connections are excluded. Any CWS or NTNC that purchases or sells water on a routine basis through an active connection to another CWS or NTNC is part of a combined distribution system. All systems included in a CDS must adhere to the schedule of the system that serves the largest population in that CDS. The system must comply with the requirements on the schedule for systems that are not a part of a CDS and for systems that serve the largest population in the CDS. The schedule for the other systems that are a part of a CDS, either wholesale or consecutive, is the same schedule as that of the system with the earliest compliance date in the CDS.

Schedule	System Population	Date by which system must begin Stage 2 compliance monitoring	
1	At least 100,000	April 1, 2012	
2	50,000-99,999	October 1, 2012	
3	10,000-49,999	October 1, 2013	
4	Fewer than 10,000	• October 1, 2013, for all GW systems and
any SW/IGW systems that did not conduct
Cryptosporidium sampling under 567—paragraph 43.11(3)“b”(2)“4”
• October 1, 2014, for SW/IGW systems that conducted Cryptosporidium sampling under 567—paragraph 43.11(3)“b”(2)“4”	
	(2)	Initiation of compliance monitoring under Stage 2. Systems shall switch from Stage 1 compliance monitoring (41.6(1)) to Stage 2 monitoring as follows:
	1.	Systems required to conduct quarterly monitoring must start monitoring in the first full calendar quarter that includes the compliance date in the preceding table.
	2.	Systems that conducted IDSE monitoring and have an approved report and that are required to conduct monitoring at a frequency less than quarterly must start monitoring in the calendar month recommended in the approved IDSE report.
	3.	Systems that were not required to prepare an IDSE report under 41.6(2) must update their Stage 1 monitoring plan to meet the Stage 2 requirements and submit it to the department for approval six months prior to the compliance date in the preceding table.
	(3)	Timing of initial determination of compliance under Stage 2.
	1.	Systems required to conduct quarterly monitoring must make compliance calculations at the end of the fourth calendar quarter that follows the compliance date or earlier if the LRAA calculated based on fewer than four quarters of data would cause the MCL to be exceeded regardless of the results of subsequent sampling. Compliance determination must continue at the end of each subsequent quarter.
	2.	Systems required to conduct monitoring at a frequency that is less than quarterly must make compliance calculations beginning with the first compliance sample taken after the compliance date.
	(4)	Monitoring and compliance.
	1.	Systems required to monitor quarterly must calculate LRAAs for TTHM and HAA5 using the monitoring results collected under this subrule and determine that each LRAA does not exceed the MCL. If the system does not complete the four consecutive quarters of monitoring, the system must calculate the compliance with the MCL based on the average of the available data from the most recent four quarters. If the system collects more than one sample per quarter at a monitoring location, all samples taken in the quarter at that location must be averaged to determine a quarterly average to be used for the LRAA calculation. If a system fails to monitor, it is in violation of the monitoring requirements for each quarter that a monitoring result would be used in calculating an LRAA.
	2.	Systems required to monitor yearly or triennially must determine that each sample collected is less than the MCL. If any sample exceeds the MCL, the system must comply with the requirements of 41.6(3)“e.” If no sample exceeds the MCL, the sample result for each monitoring location is considered to be the LRAA for that monitoring location. If a system fails to monitor, it is in violation of the monitoring requirements for each quarter that a monitoring result would be used in calculating an LRAA.
	3.	The department may grant up to an additional 24 months for compliance with MCLs and operational evaluation levels if the system is required to make capital improvements in order to comply with an MCL.
	(5)	Any CWS or NTNC system that begins using water to which a disinfectant has been added, other than ultraviolet light, after the initial compliance dates for IDSE or Stage 2 compliance monitoring must comply with this subrule.
	b. 	Monitoring plan. All systems must develop and implement a disinfection byproduct monitoring plan, which shall be kept on file at the system for review by the department and the public. The monitoring plan must contain the monitoring locations, monitoring dates, and compliance calculation procedures.
	(1)	If the system has an approved IDSE-standard monitoring plan (IDSE-SMP) report, that report contains all of the plan elements and meets this requirement.
	(2)	If the system does not have an approved IDSE-SMP report and does not have sufficient monitoring locations from its initial disinfection byproduct sampling plan, the system must identify additional locations by alternating selection of locations representing high TTHM levels and high HAA5 levels until the required number of compliance monitoring locations have been identified. The system must provide the rationale for identifying locations as having high levels of TTHM or HAA5.
	(3)	If the system does not have an approved IDSE-SMP report and has more monitoring locations from its initial Stage 1 disinfection byproduct sampling plan than the number of locations required under the Stage 2 compliance monitoring, the system must identify which locations it will use for compliance monitoring by alternating selection of locations representing high TTHM levels and high HAA5 levels until the required number of compliance monitoring locations have been identified.
	(4)	All plans must be reviewed by the system every three years and updated as system conditions change (such as changes in water quality or hydraulics, etc.).
	1.	A system may revise its monitoring plan to reflect changes in treatment, distribution system operations, and layout (including new service areas), to reflect other factors that may affect TTHM or HAA5 formation, or for department-approved reasons.
	2.	The system must consult with the department regarding the need for changes and the appropriateness of changes. The system must replace existing compliance monitoring locations that have the lowest LRAA with new locations that reflect the current distribution system locations with expected high TTHM or HAA5 levels.
	3.	The department may require modifications in the system’s monitoring plan.
	(5)	Systems are also required to maintain the disinfectant and MRDL elements of the Stage 1 monitoring plan pursuant to 41.6(1)“c”(1)“6” and 567—paragraph 43.6(1)“c”(1)“5.”
	(6)	All systems are required to have a valid disinfection byproducts monitoring plan prior to the start of compliance monitoring in 41.6(3)“a”(1).
	c. 	Routine monitoring. Systems are required to start monitoring at the locations specified in the approved disinfection byproducts monitoring plan and on the schedule specified in 41.6(3)“a”(1). Each system must monitor the disinfection byproducts at the minimum number of locations identified in the Routine Monitoring table.
Routine Monitoring

Source water type	Population size category	Monitoring frequency	Total number of distribution system monitoring location sites per monitoring period	
SW/IGW	<500	per year	2	
	500-3,300	per quarter	2	
	3,301-9,999	per quarter	2	
	10,000-49,999	per quarter	4	
	50,000-249,999	per quarter	8	
	250,000-999,999	per quarter	12	
Groundwater	<500	per year	2	
	500-9,999	per year	2	
	10,000-99,999	per quarter	4	
	100,000-499,999	per quarter	6	
	(1)	All systems must monitor during the month of highest disinfection byproduct concentrations.
	(2)	Systems on a quarterly monitoring frequency must collect samples for TTHM and HAA5 every 90 days at each monitoring location, except that SW/IGW systems serving 500 to 3,300 people may collect at one location as provided in 41.6(3)“c”(3). Each sample collected at each location must be analyzed for both TTHM and HAA5 components.
	(3)	Systems on an annual monitoring frequency and SW/IGW systems serving 500 to 3,300 people are required to collect TTHM and HAA5 samples at the locations with the highest TTHM and HAA5 concentrations, respectively. Each sample must be analyzed for both TTHM and HAA5 components. Sample collection is required from only one location if the highest TTHM concentration and the highest HAA5 concentration occur at the same location.
	(4)	Analytical methods. Systems must use an approved method listed in 41.6(1)“d”(2) for TTHM and HAA5 analyses pursuant to this subrule. Analyses must be conducted by laboratories certified for disinfection byproducts analyses in accordance with 567—Chapter 83.
	d. 	Reduced monitoring. A system may reduce monitoring to the level specified in the Reduced Monitoring table anytime the locational running annual average is less than or equal to half the MCL for TTHM and HAA5 at all monitoring locations (i.e., less than or equal to 0.040 mg/L for TTHM and 0.030 mg/L for HAA5). Only data collected under the provisions of this rule may be used to qualify for reduced monitoring.
Reduced Monitoring

Source water type	Population size category	Monitoring frequency1	Distribution system monitoring location sites per monitoring period2	
SW/IGW	<500	per year	Monitoring may not be reduced	
	500-3,300	per year	1 sample per year at the same location if the highest TTHM and HAA5 measurements occurred at the same location and in the same quarter, analyzed for both TTHM and HAA5	
	3,301-9,999	per year	2 samples: one at the location and during the quarter with the highest TTHM single measurement; one at the location and during the quarter with the highest HAA5 single measurement	
	10,000-49,999	per quarter	2 samples: one at the highest TTHM LRAA location and one at the highest HAA5 LRAA location	
	50,000-249,999	per quarter	4 samples: one sample each at the highest two TTHM LRAA locations and one sample each at the highest two HAA5 LRAA locations	
	250,000-999,999	per quarter	6 samples: one sample each at the highest three TTHM LRAA locations and one sample each at the highest three HAA5 LRAA locations	
Groundwater	<500	every third year	1 sample at the same location if the highest TTHM and HAA5 measurements occurred at the same location and in the same quarter, analyzed for both TTHM and HAA5	
	500-9,999	per year	1 sample per year at the same location if the highest TTHM and HAA5 measurements occurred at the same location and in the same quarter, analyzed for both TTHM and HAA5	
	10,000-99,999	per year	2 samples: one at the location and during the quarter with the highest TTHM single measurement; one at the location and during the quarter with the highest HAA5 single measurement	
	100,000-499,999	per quarter	2 samples: one at the highest TTHM LRAA location and one at the highest HAA5 LRAA location	
1Systems on a quarterly monitoring frequency must collect the sample(s) every 90 days.
2Each sample must be analyzed for all TTHM and HAA5 components.
	(1)	Additional source water TOC requirement for SW/IGW systems. For SW/IGW systems, the source water running annual average TOC level, before any treatment, must be less than or equal to 4.0 mg/L at each treatment plant treating surface water or influenced groundwater, based on the monitoring conducted under 567—paragraph 43.6(2)“b,” in order to qualify for reduced monitoring.
	(2)	Continued reduced monitoring frequency. Systems may remain on a reduced monitoring frequency as long as they meet the following criteria. For SW/IGW systems, the source water annual average TOC level requirement in 41.6(3)“d”(1) must continue to be met.
	1.	A system with a quarterly reduced monitoring frequency may remain on reduced monitoring as long as the TTHM LRAA is less than or equal to 0.040 mg/L and the HAA5 LRAA is less than or equal to 0.030 mg/L at each monitoring location.
	2.	A system with an annual or triennial monitoring frequency may remain on reduced monitoring as long as each TTHM sample is less than or equal to 0.060 mg/L and each HAA5 sample is less than or equal to 0.045 mg/L.
	(3)	Return to routine monitoring frequency. Systems that cannot meet the requirements for reduced monitoring must resume routine monitoring according to 41.6(3)“c” or begin increased monitoring according to 41.6(3)“e.”
	1.	A system with a quarterly reduced monitoring frequency must resume routine monitoring if the LRAA from any location exceeds either 0.040 mg/L for TTHM or 0.030 mg/L for HAA5.
	2.	A system with an annual or triennial monitoring frequency must resume routine monitoring if the annual sample at any location exceeds either 0.060 mg/L for TTHM or 0.045 mg/L for HAA5.
	3.	Any SW/IGW system must resume routine monitoring if the running annual average source water TOC level, prior to any treatment, is more than 4.0 mg/L.
	4.	In addition, the department may require any system to resume routine monitoring at the department’s discretion.
	(4)	Remaining on reduced monitoring from Stage 1 to Stage 2 transition. A system may remain on reduced monitoring after the dates listed in 41.6(3)“a”(1) if all of the following three criteria are met. If the three criteria are not met, the system must return to routine monitoring.
	1.	Under the IDSE, the system qualified for a 40/30 certification or received a very small system waiver;
	2.	The system meets the reduced monitoring criteria of this paragraph; and
	3.	The system has not changed or added locations for disinfection byproduct monitoring from those used under the Stage 1 requirements in 41.6(1).
	e. 	Increased monitoring.
	(1)	Systems that are monitoring annually or triennially must increase their monitoring frequency to quarterly if the following conditions are met.
	1.	Single result exceeds the TTHM or HAA5 MCL. A system that is monitoring annually or triennially must increase monitoring to quarterly at all locations if a single TTHM sample is greater than 0.080 mg/L or a single HAA5 sample is greater than 0.060 mg/L. The quarterly samples must be analyzed for both TTHM and HAA5 components.
	2.	Systems with a TTHM or HAA5 MCL violation. A system that is monitoring annually or triennially that is in violation of the MCL for TTHM or HAA5, based upon the LRAA, must increase monitoring to quarterly at all locations. The quarterly samples must be analyzed for both TTHM and HAA5 components. The LRAA is calculated based on four consecutive quarters of monitoring or based on fewer quarters of data if the MCL would be exceeded regardless of the monitoring results of subsequent quarters.
	(2)	Systems on a quarterly monitoring frequency during Stage 1 to Stage 2 transition. A system that was on increased monitoring under Stage 1 must remain on increased monitoring until the system qualifies for a return to routine monitoring under 41.6(3)“e”(3). The system must conduct the increased monitoring at the monitoring locations in the monitoring plan developed under 41.6(3)“b,” beginning on the date identified in 41.6(3)“a”(1).
	(3)	Return to routine monitoring frequency. A system may return to routine monitoring once the system has conducted increased monitoring for at least four consecutive quarters and the LRAA for every monitoring location is less than or equal to 0.060 mg/L for TTHM and less than or equal to 0.045 mg/L for HAA5. The system may not have any monitoring violations during the most recent four consecutive quarters.
	f. 	Operational evaluation level (OEL).
	(1)	TTHM operational evaluation level. The TTHM operational evaluation level is determined by the sum of the two previous quarters’ TTHM results plus twice the current quarter’s TTHM result, divided by 4 to determine an average. If that average exceeds 0.080 mg/L, the system has exceeded the TTHM operational evaluation level.
	(2)	HAA5 operational evaluation level. The HAA5 operational evaluation level is determined by the sum of the two previous quarters’ HAA5 results plus twice the current quarter’s HAA5 result, divided by 4 to determine an average. If that average exceeds 0.060 mg/L, the system has exceeded the HAA5 operational evaluation level.
	(3)	A system must calculate the operational evaluation level at any monitoring location that has a single analytical result in excess of the TTHM or HAA5 MCL in the analytical data used to calculate the current 12-month LRAA. A system must determine compliance with the OEL every quarter.
	(4)	Requirements when the operational evaluation level is exceeded. The system must conduct an operational evaluation and submit a written report of the evaluation to the department within 90 days after the system is notified of the analytical result that caused the system to exceed the operational evaluation level. The written report must be made available to the public upon request. The report must include an examination of system treatment and distribution operational practices, including storage tank operations, excess storage capacity, distribution system flushing, changes in source water or source water quality, and treatment changes or problems that may contribute to disinfection byproduct formation, and what steps could be considered to minimize future exceedances.
	1.	The system may make a request to the department to limit the scope of the examination if the system is able to identify the cause of the operational evaluation level exceedance. The 90-day deadline for submitting the written report cannot be extended.
	2.	The system must have department approval to limit the scope of the examination. The approval must be in writing and kept with the completed report.
	g. 	Reporting. All systems required to comply with this rule must meet the reporting requirements pursuant to 567—paragraph 42.4(3)“d.”
	h. 	Record keeping. All systems required to comply with this rule must retain the monitoring plans and analytical results as required by 567—paragraph 42.5(1)“h.”
[ARC 9915B, IAB 12/14/11, effective 1/18/12; ARC 3735C, IAB 4/11/18, effective 5/16/18]
567—41.7(455B) Groundwater rule: sanitary survey, microbial source water monitoring, treatment technique.
	41.7(1) General requirements.
	a. 	Scope. The requirements of this rule constitute national primary drinking water regulations.
	b. 	Applicability. This rule applies to all public water systems that use groundwater except that it does not apply to public water systems that combine all of their groundwater with surface water or with influenced groundwater prior to treatment under 567—43.5(455B). For the purposes of this rule, “groundwater system” is defined as any public water system meeting this applicability statement, including consecutive systems receiving finished groundwater. For the purposes of this rule, “4-log treatment of viruses” means treatment that includes inactivation, removal, or a department-approved combination of inactivation and removal before or at the first customer of 4-log (99.99%) of viruses.
	c. 	General requirements. Systems subject to this rule must comply with the following requirements:
	(1)	Sanitary survey information requirements for all groundwater systems as described in 41.7(2).
	(2)	Microbial source water monitoring requirements for groundwater systems that do not treat all of their groundwater to at least 99.99 percent (4-log) treatment of viruses, using inactivation, removal, or a department-approved combination of inactivation and removal before or at the first customer, as described in 41.7(3).
	(3)	Treatment technique requirements, as described in 41.7(4), that apply to groundwater systems that have fecally contaminated source waters, as determined by source water monitoring conducted under 41.7(3), or that have significant deficiencies that are identified by the department. A groundwater system with fecally contaminated source water or with significant deficiencies subject to the treatment technique requirements of this rule must implement one or more of the following corrective action options:
	1.	Correct all significant deficiencies;
	2.	Provide an alternate source of water;
	3.	Eliminate the source of contamination; or
	4.	Provide treatment that reliably achieves at least 4-log treatment of viruses (using inactivation, removal, or a department-approved combination of 4-log virus inactivation and removal) before or at the first customer.
	(4)	Groundwater systems that provide at least 4-log treatment of viruses are required to conduct compliance monitoring to demonstrate treatment effectiveness, as described in 41.7(4).
	(5)	If requested by the department, groundwater systems must provide the department with any existing information that will enable the department to perform a hydrogeologic sensitivity assessment. For the purposes of this rule, “hydrogeologic sensitivity assessment” is a determination of whether groundwater systems obtain water from hydrogeologically sensitive settings.
	(6)	Certified laboratory requirements. Analyses under this rule shall only be conducted by laboratories that have been certified by the department and are in compliance with the requirements of 567—Chapter 83.
	41.7(2) Sanitary surveys for groundwater systems. For the purposes of this rule, a “sanitary survey,” as conducted by the department in accordance with 567—subrule 43.1(7), includes but is not limited to the following: an on-site review of the water sources (identifying sources of contamination using results of source water assessments or other relevant information where available), facilities, equipment, operation, maintenance, and monitoring compliance of a public water system to evaluate the adequacy of the system, its sources and operations and the distribution of safe drinking water.
	41.7(3) Groundwater source microbial monitoring and analytical methods. A groundwater system that has a department-approved 4-log treatment process for viruses and is fulfilling the requirements of 41.7(4)“b” is not required to conduct the triggered source water monitoring under 41.7(3)“a.”
	a. 	Triggered source water monitoring.
	(1)	General requirements. A groundwater system must conduct triggered source water monitoring if the conditions identified as follows exist:
	1.	The system does not provide at least 4-log treatment of viruses for each groundwater source; and
	2.	The system is notified that a sample collected under 41.2(1)“e” through 41.2(1)“i” is total coliform-positive, and the sample is not invalidated under 41.2(1)“d.”
	(2)	Sampling requirements. A groundwater system must collect at least one groundwater source sample from each groundwater source in use at the time the total coliform-positive sample was collected under 41.2(1)“e” through 41.2(1)“i” that could have reasonably contributed to the positive sample. The source sample must be collected within 24 hours of when the system is notified of the total coliform-positive sample.
	1.	The department may extend the 24-hour time limit on a case-by-case basis if the system cannot collect the groundwater source water sample within 24 hours due to circumstances beyond the system’s control. In the case of an extension, the department must specify how much time the system has to collect the sample.
	2.	A groundwater system serving 1,000 or fewer people may use a repeat sample collected from a groundwater source to meet both the requirements of 41.2(1)“j” and to satisfy the monitoring requirements of 41.7(3)“a” if:
	●	The department approves the use of E. coli as the fecal indicator,
	●	The system only has one groundwater source required to be sampled,
	●	The system has no treatment, and
	●	Should the source water sample be E. coli-positive, the system would incur an acute coliform bacteria maximum contaminant level violation, must comply with Tier 1 public notification requirements, and must also comply with the additional sample monitoring in 41.7(3)“a”(3).
	(3)	Additional samples required. Unless the department requires corrective action for a valid triggered source water sample that tested positive for the fecal indicator, the system must collect five additional source water samples from that same source within 24 hours of being notified of the fecal indicator-positive sample result.
	(4)	Further requirements for consecutive and wholesale systems.
	1.	In addition to the other requirements in 41.7(3)“a,” a consecutive groundwater system that has a total coliform-positive sample collected under 41.2(1)“f” through 41.2(1)“i” must notify the wholesale system(s) within 24 hours of being notified of the total coliform-positive sample.
	2.	In addition to the other requirements in 41.7(3)“a,” a wholesale groundwater system that does not provide the 4-log treatment of viruses as described in 41.7(3) must comply with the following:
	●	A wholesale groundwater system that receives notice from a consecutive system it serves that a sample collected under 41.2(1)“f” through 41.2(1)“i” is total coliform-positive must, within 24 hours of being notified, collect triggered sample(s) from its groundwater source(s) under 41.7(3)“a”(2) and analyze the sample(s) for a fecal indicator.
	●	If the triggered source sample(s) is fecal indicator-positive, the wholesale groundwater system must notify all consecutive systems served by that groundwater source of the fecal indicator-positive result within 24 hours of being notified of the result and must collect the required additional five samples from the source within 24 hours under 41.7(3)“a”(3).
	(5)	Exceptions to the triggered source water monitoring requirements. A groundwater system is not required to comply with the source water monitoring requirements of 41.7(3)“a” if either of the following conditions exists:
	1.	The department determines and documents in writing that the total coliform-positive sample collected under 41.2(1)“e” through 41.2(1)“i” is caused by a distribution system deficiency; or
	2.	The total coliform-positive sample collected under 41.2(1)“e” through 41.2(1)“i” is collected at a location that meets department criteria for distribution system conditions that will cause total coliform-positive samples.
	b. 	Assessment source water monitoring. If directed by the department, groundwater systems must conduct assessment source water monitoring that meets department-determined requirements for such monitoring. A groundwater system conducting assessment source water monitoring may use a triggered source water sample collected under 41.7(3)“a”(2) to meet the requirements of this paragraph. Department-determined assessment source water monitoring requirements may include:
	(1)	Collection of a total of 12 groundwater source samples that represent each month the system provides groundwater to the public;
	(2)	Collection of samples from each well unless the system obtains written department approval to conduct monitoring at one or more wells within the groundwater system that are representative of multiple wells used by that system and that draw water from the same hydrogeologic setting;
	(3)	Collection of a standard sample volume of at least 100 mL for fecal indicator analysis regardless of technical indicator or analytical method used;
	(4)	Analysis of all groundwater source samples using one of the analytical methods listed in 41.7(3)“c” for the presence of E. coli, enterococci, or coliphage;
	(5)	Collection of groundwater source samples at a location before any treatment of the groundwater source unless the department approves a sampling location after treatment; and
	(6)	Collection of groundwater source samples at the well itself unless the system’s configuration does not allow for sampling at the well itself and the department approves an alternate sampling location that is representative of the water quality of that well.
	c. 	Analytical methods.
	(1)	A groundwater system subject to the source water monitoring requirements of this rule must collect a standard sample volume of at least 100 mL for fecal indicator analysis regardless of the fecal indicator or analytical method used.
	(2)	A groundwater system must analyze all groundwater source samples collected under 567—41.7(455B) using one of the analytical methods in the following table for the presence of E. coli, enterococci, or coliphage.
Analytical Methods for Source Water Monitoring

Fecal Indicator1	Methodology	Method Citation		
E. coli	Colilert3	9223B2, 12, 13		
		9223 B-97, B-0418		
	Colisure3	9223B2, 12, 13		
		9223B-97, B-0418		
	Membrane filter method with MI agar	EPA Method 16044		
	Colilert-18	9223B2, 12, 13		
		9223B-97, B-0418		
	m-ColiBlue24 Test5	 		
	E*Colite Test6	 		
	EC-MUG7	9221F2, 13		
		9221 F-0618		
	NA-MUG7	9222G2		
	Readycult	Readycult14		
	Colitag	Modified Colitag15		
	Chromocult	Chromocult16		
	Tecta EC/TC	Tecta EC/TC19		
Enterococci	Multiple-tube technique	9230B2
9230 B-0418		
	Membrane filter technique	9230C2		
	Membrane filter technique	EPA Method 16008		
	Enterolert9	 		
Coliphage	Two-step enrichment presence-absence procedure	EPA Method 160110, FastPhage17		
				
	Single agar layer procedure	EPA Method 160211		

<fo:wrapper font-size="8pt">Analyses must be conducted in accordance with the documents listed below. The Director of the Federal Register approves the incorporation by reference of the documents listed in footnotes 2 through 11 in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies of the documents may be obtained from the sources listed below. Copies may be inspected at EPA’s Drinking Water Docket, EPA West, 1301 Constitution Avenue, NW, EPA West Room B102, Washington, DC 20460; (telephone: (202)566-2426); or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202)741-6030, or go to: www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. The address for EPA’s Water Resource Center, referenced in several of the footnotes, is EPA Water Resource Center (RC-4100T), 1200 Pennsylvania Avenue, NW, Washington, DC 20460.</fo:wrapper>	
1The time from sample collection to initiation of analysis may not exceed 30 hours. The groundwater system is encouraged but is not required to hold samples below 10°C during transit.
2Methods are described in Standard Methods for the Examination of Water and Wastewater, 20th edition (1998), and copies may be obtained from the American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710.
3Medium is available through IDEXX Laboratories, Inc., One IDEXX Drive, Westbrook, ME 04092.
4EPA Method 1604: Total Coliforms and Escherichia coli in Water by Membrane Filtration Using a Simultaneous Detection Technique (MI Medium); September 2002, EPA 821-R-02-024. Method is available at www.nemi.gov.
5A description of the m-ColiBlue24 Test, “Total Coliforms and E. coli Membrane Filtration Method with m-ColiBlue24 Broth,” Method No.	10029, Revision 2, August 17, 1999, is available from Hach Company, 100 Dayton Avenue, Ames, IA 50010.
6A description of the E*Colite Test, “Charm E*Colite Presence/Absence Test for Detection and Identification of Coliform Bacteria and Escherichia coli in Drinking Water,” January 9, 1998, is available from Charm Sciences, Inc., 659 Andover Street, Lawrence, MA 01843-1032.
7EC-MUG (Method 9221F) or NA-MUG (Method 9222G) can be used for E. coli testing step as described in 41.2(1)“f”(6) or (7) after use of Standard Method 9221B, 9221D, 9222B, or 9222C.
8EPA Method 1600: Enterococci in Water by Membrane Filtration Using Membrane-Enterococcus Indoxyl-β-D-Glucoside Agar (MEI), EPA 821-R-02-022 (September 2002), is an approved variation of Standard Method 9230C. The method is available at www.nemi.gov. The holding time and temperature for groundwater samples is specified in footnote 1 above, rather than as specified in Section 8 of EPA Method 1600.
9Medium is available through IDEXX Laboratories, Inc., One IDEXX Drive, Westbrook, ME 04092. Preparation and use of the medium is set forth in the article “Evaluation of Enterolert for Enumeration of Enterococci in Recreational Waters” by Budnick, G.E., Howard, R.T., and Mayo, D.R., 1996, Applied and Environmental Microbiology, 62:3881-3884.
10EPA Method 1601: Male-Specific (F+) and Somatic Coliphage in Water by Two-Step Enrichment Procedure; April 2001, EPA 821-R-01-030. Method is available at www.nemi.gov.
11EPA Method 1602: Male-Specific (F+) and Somatic Coliphage in Water by Single Agar Layer (SAL) Procedure; April 2001, EPA 821-R-01-029. Method is available at www.nemi.gov.
12Standard Methods for the Examination of Water and Wastewater, 21st edition (2005). Available from the American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710.
13Standard Methods for the Examination of Water and Wastewater, 22nd edition (2012). Available from the American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710.
14Readycult Method, “Readycult Coliforms 100 Presence/Absence Test for Detection and Identification of Coliform Bacteria and Escherichia coli in Finished Waters,” January 2007, Version 1.1. Available from EMD Millipore, 290 Concord Road, Billerica, MA 01821.
15Modified Colitag Method, “Modified Colitag Test Method for the Simultaneous Detection of E. coli and Other Total Coliforms in Water (ATP D05-0035),” August 28, 2009. Available from www.nemi.gov or CPI International, 5580 Skylane Blvd., Santa Rosa, CA 95403.
16Chromocult Method, “Chromocult Coliform Agar Presence/Absence Membrane Filter Test Method for Detection and Identification of Coliform Bacteria and Escherichia coli in Finished Waters,” November 2000, Version 1.0. Available from EMD Millipore, 290 Concord Road, Billerica, MA 01821.
17Charm Sciences, Inc., “FastPhage Test Procedure. Presence/Absence for Coliphage in Ground Water with Same Day Positive Prediction,” Version 009, November 2012. Available at www.charmsciences.com.
18Standard Methods Online is available at www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only online versions that may be used.
19Tecta EC/TC. “Presence/Absence Method for Simultaneous Detection of Total Coliforms and Escherichia coli in Drinking Water,” April 2014. Available from Veolia Water Solutions and Technologies, Suite 4697, Biosciences Complex, 116 Barrie Street, Kingston, Ontario, Canada K7L 3N6.
	d. 	Invalidation of a fecal indicator-positive groundwater source sample.
	(1)	A groundwater system may obtain invalidation from the department of a fecal indicator-positive groundwater source sample collected under 41.7(3)“a” only under these conditions:
	1.	The system provides the department with written notice from the laboratory that improper sample analysis occurred; or
	2.	The department determines and documents in writing that there is substantial evidence that a fecal indicator-positive groundwater source sample is not related to source water quality.
	(2)	If the department invalidates a fecal indicator-positive groundwater source sample, the system must collect another source water sample under 41.7(3)“a” within 24 hours of being notified by the department of its invalidation decision. The sample must be analyzed for the same fecal indicator using the analytical methods in 41.7(3)“c.” The department may extend the 24-hour time limit on a case-by-case basis if the system cannot collect the source water sample within 24 hours due to circumstances beyond the system’s control. In the case of an extension, the department must specify how much time the system has to collect the sample.
	e. 	Sampling location.
	(1)	Any groundwater source sample required under 41.7(3)“a” must be collected at a location prior to any treatment of the groundwater source unless the department approves a sampling location after treatment.
	(2)	If the system’s configuration does not allow for sampling at the well itself, the system may collect a sample at a department-approved location to meet the requirements of 41.7(3)“a” if the sample is representative of the water quality of that well.
	f. 	New sources. A groundwater system that places a new groundwater source into service must conduct assessment source water monitoring as directed by the department to include those items listed in 41.7(3)“b”(3) to (6). If directed by the department, the system must begin monitoring before the groundwater source is used to provide water to the public.
	g. 	Public notification. A system with a groundwater source sample collected under 41.7(3)“a” or 41.7(3)“b” that is fecal indicator-positive and that is not invalidated under 41.7(3)“d,” including consecutive systems served by the groundwater source, must conduct Tier 1 public notification under 567—subrule 42.1(2).
	h. 	Monitoring violations. Failure to meet the requirements of 41.7(3)“a” through 41.7(3)“f” is a monitoring violation and requires the system to provide Tier 3 public notification under 567—subrule 42.1(4).
	41.7(4) Treatment technique requirements for groundwater systems.
	a. 	Groundwater systems with significant deficiencies or source water fecal contamination.
	(1)	The treatment technique requirements of this subrule, 41.7(4), must be met by groundwater systems when a significant deficiency is identified or when a groundwater source sample collected under 41.7(3)“a”(3) is fecal indicator-positive.
	(2)	If directed by the department, a groundwater system with a groundwater source sample collected under 41.7(3)“a”(2), 41.7(3)“a”(4), or 41.7(3)“b” that is fecal indicator-positive must comply with the treatment technique requirements of 41.7(4).
	(3)	When a significant deficiency is identified at a surface water or influenced groundwater system that also uses a groundwater source not under the influence of surface water, the system must comply with provisions of 41.7(4)“a” except in cases where the department determines that the significant deficiency is in a portion of the distribution system that is served solely by the surface water or influenced groundwater source.
	(4)	Unless the department directs the groundwater system to implement a specific corrective action, the groundwater system must consult with the department regarding the appropriate corrective action within 30 days of receiving written notice from the department of a significant deficiency, written notice from a laboratory that a groundwater source sample collected under 41.7(3)“a”(3) was found to be fecal indicator-positive, or direction from the department that a fecal indicator-positive sample collected under 41.7(3)“a”(2), 41.7(3)“a”(4), or 41.7(3)“b” requires corrective action. For the purposes of 41.7(4), significant deficiencies include, but are not limited to, defects in design, operation, or maintenance, or a failure or malfunction of the sources, treatment, storage, or distribution system that the department determines to be causing, or have potential for causing, the introduction of contamination into the water delivered to consumers.
	(5)	Within 120 days, or earlier if directed by the department, of receiving written notification from the department of a significant deficiency, written notice from a laboratory that a groundwater source sample collected under 41.7(3)“a”(3) was found to be fecal indicator-positive, or direction from the department that a fecal indicator-positive sample collected under 41.7(3)“a”(2), 41.7(3)“a”(4), or 41.7(3)“b” requires corrective action, the groundwater system must either:
	1.	Have completed corrective action in accordance with applicable department plan review processes or other department guidance or direction, if any, including department-specified interim measures; or
	2.	Be in compliance with a department-approved corrective action plan and schedule subject to the specified conditions as follows:
	●	Any subsequent modifications to a department-approved corrective action plan and schedule must also be approved by the department; and
	●	If the department specifies interim measures for protection of the public health pending department approval of the corrective action plan and schedule, or pending completion of the corrective action plan, the system must comply with these interim measures as well as with any schedule specified by the department.
	(6)	Corrective action alternatives. Groundwater systems that meet the conditions of 41.7(4)“a”(1) or (2) must implement one or more of the following corrective action alternatives:
	1.	Correct all significant deficiencies;
	2.	Provide an alternate source of water;
	3.	Eliminate the source of contamination; or
	4.	Provide treatment that reliably achieves at least 4-log treatment of viruses for the groundwater source.
	(7)	Special notice to the public of significant deficiencies or source water fecal contamination.
	1.	In addition to the applicable Tier 1 public notification requirements of 567—subrule 42.1(2), a community groundwater system that receives notice from the department of a significant deficiency or notification of a fecal indicator-positive groundwater source sample that is not invalidated by the department under 41.7(3)“d” must inform the public served by the water system under 567—subparagraph 42.3(3)“h”(5) of the fecal indicator-positive source sample or of any significant deficiency that has not been corrected. The system must continue to inform the public annually until the significant deficiency is corrected or the fecal contamination in the groundwater source is determined by the department to be corrected under 41.7(3)“a”(5).
	2.	In addition to the applicable Tier 1 public notification requirements of 567—subrule 42.1(2), a noncommunity groundwater system that receives notice from the department of a significant deficiency must inform the public served by the water systems in a manner approved by the department of any significant deficiency that has not been corrected within 12 months of being notified by the department or earlier if directed by the department. The system must continue to inform the public annually until the significant deficiency is corrected. The information must include:
	●	The nature of the significant deficiency and the date the significant deficiency was identified by the department;
	●	The department-approved plan and schedule for correction of the significant deficiency, including interim measures, progress to date, and any interim measures completed; and
	●	For systems with a large proportion of non-English speaking consumers, as determined by the department, information in the applicable language(s) regarding the importance of the notice or a telephone number or address where consumers may contact the system to obtain a translated copy of the notice or assistance in the appropriate language.
	3.	If directed by the department, a noncommunity water system with significant deficiencies that have been corrected must inform its customers of the significant deficiencies, how the deficiencies were corrected, and the dates of correction under 41.7(4)“a”(7)“2.”
	b. 	Compliance monitoring.
	(1)	Existing groundwater sources. A groundwater system that provides at least 4-log treatment of viruses must make a written application to the department in order to avoid the source water monitoring requirements of 41.7(3). Notification to the department must include engineering, operational, or other information that the department requests to evaluate the submission. The department must approve the 4-log request in writing before the system can avoid the groundwater source monitoring requirements. The system’s operation permit will include the mandatory operational requirements for the approved 4-log virus treatment. If the system subsequently discontinues 4-log treatment of viruses of a groundwater source or no longer wishes to be exempt from the groundwater source monitoring requirements, the system must conduct groundwater source monitoring as required under 41.7(3).
	(2)	New groundwater sources. A groundwater system that places a groundwater source in service that is not required to meet the source water monitoring requirements of 41.7(4) because the system provides at least 4-log treatment of viruses for the groundwater source must comply with the following requirements:
	1.	The system must notify the department in writing that it provides at least 4-log treatment of viruses for the groundwater source. Notification to the department must include engineering, operational, or other information that the department requests to evaluate the submission. The contact time values for inactivation of viruses using free chlorine, chlorine dioxide, and ozone are listed in 567—Chapter 43, Appendix C. No CT table is provided for chloramines and total chlorine because the CT values would be prohibitively high for groundwater systems.
	2.	The system must conduct compliance monitoring as required under 41.7(4)“b”(3) within 30 days of placing the source in service.
	3.	The system must conduct groundwater source monitoring under 41.7(3) if the system subsequently discontinues 4-log treatment of viruses for the groundwater source.
	(3)	Monitoring requirements. A groundwater system subject to the requirements of 41.7(4)“a” and 41.7(4)“b”(1) and (2) must monitor the effectiveness and reliability of treatment for that groundwater source before or at the first customer as follows:
	1.	Chemical disinfection.
	●	A groundwater system serving more than 3,300 people must continuously monitor the residual disinfectant concentration, using analytical methods specified in 567—subparagraph 43.5(4)“a”(5), at a location approved by the department and must record the lowest residual disinfectant concentration each day that water from the groundwater source is served to the public. The groundwater system must maintain the department-determined minimum residual disinfectant concentration every day the groundwater system serves water from the groundwater source to the public. If there is a failure in the continuous monitoring equipment, the groundwater system must conduct grab sampling every four hours until the continuous monitoring equipment is returned to service. The system must resume continuous residual disinfectant monitoring within 14 days.
	●	A groundwater system serving 3,300 or fewer people must monitor the residual disinfectant concentration using analytical methods specified in 567—subparagraph 43.5(4)“a”(5) at a location approved by the department and must record the residual disinfectant concentration each day that water from the groundwater source is served to the public. The groundwater system must maintain the department-determined minimum residual disinfectant concentration every day the groundwater system serves water from the groundwater source to the public. The groundwater system must take a daily grab sample during the hour of peak flow or at another time specified by the department. If any daily grab sample measurement falls below the department-determined minimum residual disinfectant concentration, the groundwater system must take follow-up samples every four hours until the residual disinfectant concentration is restored to the department-determined minimum level. Alternatively, a groundwater system that serves 3,300 or fewer people may monitor continuously and meet the requirements of 41.7(4)“b”(3)“1,” first bulleted paragraph.
	2.	Membrane filtration. A groundwater system that uses membrane filtration to meet the requirements of 41.7(4)“b” to provide at least 4-log treatment of viruses must monitor the membrane filtration process in accordance with all department-specified monitoring requirements and must operate the membrane filtration in accordance with all department-specified compliance requirements. A groundwater system that uses membrane filtration is in compliance with the requirement to achieve at least 4-log removal of viruses when:
	●	The membrane has an absolute molecular weight cut-off (MWCO), or an alternate parameter that describes the exclusion characteristics of the membrane, that can reliably achieve at least 4-log removal of viruses;
	●	The membrane process is operated in accordance with department-specified compliance requirements; and
	●	The integrity of the membrane is intact.
	3.	Alternative treatment. A groundwater system that uses a department-approved alternative treatment to meet the requirements of 41.7(4)“b” by providing at least 4-log treatment of viruses must:
	●	Monitor the alternative treatment in accordance with all department-specified monitoring requirements; and
	●	Operate the alternative treatment in accordance with all compliance requirements that the department determines to be necessary to achieve at least 4-log treatment of viruses.
	c. 	Discontinuing treatment. A groundwater system may discontinue 4-log treatment of viruses for a groundwater source if the department determines and documents in writing that 4-log treatment of viruses is no longer necessary for that groundwater source. A system that discontinues 4-log treatment of viruses is subject to the source water monitoring and analytical methods requirements of 41.7(3).
	d. 	Monitoring violation. Failure to meet the monitoring requirements of 41.7(4)“b” is a monitoring violation and requires the groundwater system to provide Tier 3 public notification under 567—subrule 42.1(4).
	41.7(5) Treatment technique violations for groundwater systems. A groundwater system must give Tier 2 public notification under 567—subrule 42.1(3) for the treatment technique violations specified in 41.7(5)“a,” 41.7(5)“b,” and 41.7(5)“c.”
	a. 	Significant deficiency. A groundwater system with a significant deficiency is in violation of the treatment technique requirement if, within 120 days (or earlier if directed by the department) of receiving written notice from the department of the significant deficiency, the system:
	(1)	Does not complete corrective action in accordance with any applicable department plan review processes or other department guidance and direction, including department-specified interim actions and measures; or
	(2)	Is not in compliance with a department-approved corrective action plan and schedule.
	b. 	Fecal indicator-positive source sample. Unless the department invalidates a fecal indicator-positive groundwater source sample under 41.7(3)“d”(1), a groundwater system is in violation of the treatment technique requirement if, within 120 days (or earlier if directed by the department) of meeting the conditions of 41.7(4)“a”(1) or (2), the system:
	(1)	Does not complete corrective action in accordance with any applicable department plan review processes or other department guidance and direction, including department-specified interim measures; or
	(2)	Is not in compliance with a department-approved corrective action plan and schedule.
	c. 	Failure to maintain 4-log treatment. A groundwater system subject to the requirements of 41.7(4)“b”(3) that fails to maintain at least 4-log treatment of viruses for a groundwater source is in violation of the treatment technique requirement if the failure is not corrected within four hours of the determination that the system is not maintaining at least 4-log treatment of viruses before or at the first customer.
	41.7(6) Reporting and record keeping for groundwater systems.
	a. 	Reporting. In addition to meeting the requirements of 567—subrule 42.4(1), a groundwater system regulated under this rule must provide the following information to the department:
	(1)	A groundwater system conducting compliance monitoring under 41.7(4)“b” must notify the department any time the system fails to meet any of the department-specified requirements for 4-log virus treatment including, but not limited to, minimum residual disinfectant concentration, membrane operating criteria or membrane integrity, and alternative treatment operating criteria, if operation in accordance with the criteria or requirements is not restored within four hours. The groundwater system must notify the department as soon as possible, but in no case later than the end of the next business day.
	(2)	After completing any corrective action under 41.7(4)“a,” a groundwater system must notify the department within 30 days of completion of the corrective action.
	(3)	If a groundwater system subject to the requirements of 41.7(3)“a” does not conduct source water monitoring under 41.7(3)“a”(5)“2,” the system must provide documentation to the department within 30 days of the total coliform-positive sample that it met the department’s criteria.
	b. 	Record keeping. In addition to the requirements in 567—subrule 42.5(1), a groundwater system regulated under this rule must maintain the following information in its records:
	(1)	Documentation of corrective actions, which must be kept for a period of not less than ten years.
	(2)	Documentation of notice to the public as required under 41.7(4)“a”(7), which must be kept for a period of not less than three years.
	(3)	Records of decisions under 41.7(3)“a”(5)“2” and records of invalidation of fecal indicator-positive groundwater source samples under 41.7(3)“d”(1), both of which must be kept for a period of not less than five years.
	(4)	For consecutive systems, documentation of notification to the wholesale system(s) of total coliform-positive samples that are not invalidated under 41.2(1)“d,” which must be kept for a period of not less than five years.
	(5)	For systems, including wholesale systems, that are required to perform compliance monitoring under 41.7(4)“b”(1), the following documentation must be maintained:
	1.	Records of the department-specified minimum disinfectant residual, which must be kept for a period of not less than ten years.
	2.	Records of the lowest daily residual disinfectant concentration and records of the date and duration of any failure to maintain the department-prescribed minimum residual disinfectant concentration for a period of more than four hours, both of which must be kept for a period of not less than five years.
	3.	Records of department-specified compliance requirements for membrane filtration and of parameters specified by the department for department-approved alternative treatment and records of the date and duration of any failure to meet the membrane operating, membrane integrity, or alternative treatment operating requirements for more than four hours. Documentation shall be kept for a period of not less than five years.
[ARC 3735C, IAB 4/11/18, effective 5/16/18]
567—41.8(455B) Radionuclides.
	41.8(1) Radionuclides.
	a. 	Applicability.
	(1)	This rule applies to all community public water supplies, and specifies the radionuclide maximum contaminant levels, analytical methodology requirements, and monitoring requirements. The radionuclide reporting requirements are listed in 567—subrule 42.4(1), the public notice requirements are listed in rule 567—42.1(455B), and the best available technology is listed in 567—subparagraph 43.3(10)“b”(3). All CWSs must comply with the requirements and maximum contaminant levels for gross alpha particle activity, radium-226, radium-228, uranium, beta particle activity, and photon emitter radioactivity. Only those CWSs designated by the department to be vulnerable to man-made radioactivity contamination are required to monitor for beta particle activity and photon emitter radioactivity. To determine whether a system is vulnerable to man-made nuclear radioactivity, the department will evaluate proximity to a nuclear facility, source water, historical analytical data, ongoing surveillance data from the nuclear facility, and any other factor considered by the department to be relevant to the vulnerability determination.
	(2)	Compliance dates. Community water systems must comply with the MCLs listed in 41.8(1)“b”(1) beginning December 8, 2003. Compliance shall be determined in accordance with 41.8(1)“c” through 41.8(1)“f.” Compliance with the radionuclides reporting requirements is required by December 8, 2003. All CWSs must conduct initial monitoring to determine compliance with 41.8(1)“b”(1) by December 31, 2007.
	b. 	Maximum contaminant levels for radionuclides.
	(1)	Gross alpha particle activity, radium-226, radium-228, and uranium MCLs. The following table specifies the MCLs for gross alpha particles, radium, and uranium radionuclides:

Contaminant	Maximum Contaminant Level	
Gross alpha particle activity, including Radium-226 but excluding radon and uranium	15 pCi/L	
Combined Radium-226 and Radium-228	5 pCi/L1	
Uranium	30 μg/L	
1The combined radium-226 and radium-228 value is determined by the addition of the results of the analysis for radium-226 and the analysis for radium-228.
	(2)	Beta particle activity and photon radioactivity MCLs.
	1.	The average annual concentration of beta particle and photon radioactivity from man-made radionuclides in drinking water must not produce an annual dose equivalent to the total body or any internal organ greater than 4 millirem/year.
	2.	Except for the radionuclides listed below, the concentration of man-made radionuclides causing 4 millirems total body or organ dose equivalents must be calculated on the basis of 2 liter per day drinking water intake, using the 168-hour data lists in “Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides in Air and in Water for Occupational Exposure,” National Bureau of Standards Handbook 69 as amended August 1963, United States Department of Commerce. If two or more radionuclides are present, the sum of their annual dose equivalent to the total body or to any organ shall not exceed 4 millirems/year.
Average Annual Concentrations Assumed to Produce a
Total Body or Organ Dose of 4 mrem/year

Radionuclide	Critical Organ	Concentration	
Strontium-90	Bone marrow	8 pCi/L	
Tritium	Total body	20,000 pCi/L	
	c. 	Compliance determinations. Compliance with 41.8(1)“b” will be determined based on the analytical results obtained at each sampling point. If one sampling point is in violation of an MCL, the system is in violation of the MCL. If the system is in violation of an MCL, the supplier of the water is required to give notice to the department in accordance with 567—subrule 42.4(1) and to notify the public as required by 567—42.1(455B).
	(1)	Detection limits. For the purposes of monitoring gross alpha particle activity, radium-226, radium-228, uranium, and beta particle and photon radioactivity in drinking water, “detection limit” is defined in this subparagraph.
	1.	For the purpose of monitoring radioactivity concentration in drinking water, the required sensitivity of the radioanalysis is defined in terms of a detection limit. The detection limit shall be that concentration which can be counted with a precision of plus or minus 100 percent at the confidence level (1.960 sigma where sigma is the standard deviation of the net counting rate of the sample).
	2.	To determine compliance with 41.8(1)“b”(1), the detection limit shall not exceed the following concentrations:
Detection Limits for Gross Alpha Particle Activity,
Radium-226, Radium-228, and Uranium

Contaminant	Detection Limit	
Gross alpha particle activity	3 pCi/L	
Radium-226	1 pCi/L	
Radium-228	1 pCi/L	
Uranium	1 μg/L	
3. To determine compliance with 41.8(1)“b”(2), the detection limits shall not exceed the following concentrations:
Detection Limits for Man-Made
Beta Particle and Photon Emitters

Contaminant	Detection Limit	
Gross beta	4 pCi/L	
Cesium-134	10 pCi/L	
Iodine-131	1 pCi/L	
Strontium-89	10 pCi/L	
Strontium-90	2 pCi/L	
Tritium	1,000 pCi/L	
Other radionuclides	1/10 of the applicable limit	
	(2)	Compliance determination.
	1.	For systems monitoring more than once per year (i.e., quarterly), compliance with the MCL is determined by a running annual average at each sampling point. If the average of any sampling point is greater than the MCL, the system is immediately in violation of the MCL. If any sample result causes the running annual average to exceed the MCL at any sample point, the system is immediately in violation of the MCL.
	2.	Systems monitoring annually or less frequently (i.e., one-, three-, six-, or nine-year frequency), and whose sample result exceeds the MCL, must revert to quarterly sampling for that contaminant during the next quarter. Systems are required to conduct quarterly monitoring only at the source/entry point at which the sample was collected and for the specific contaminant that triggered the system into the increased monitoring frequency. Systems triggered into increased monitoring will not be considered in violation of the MCL until they have completed one year of quarterly sampling. If any sample result causes the running annual average to exceed the MCL at any sample point, the system is immediately in violation of the MCL.
	3.	Systems must include all samples taken and analyzed under the provisions of this rule in determining compliance, even if that number is greater than the minimum required by the department.
	4.	If a system does not collect all required samples when compliance is based on a running annual average of quarterly samples, compliance will be based on the running average of the samples collected.
	5.	If a sample result is less than the detection limit, a value of zero will be used to calculate the annual average.
	6.	The department may invalidate results of obvious sampling or analytical errors.
	7.	Averaging and significant figures. To judge compliance with the maximum contaminant levels listed in 41.8(1)“b,” averages of data shall be used and shall be rounded to the same number of significant figures as the maximum contaminant level for the substance in question.
	(3)	The department will determine compliance or initiate enforcement action based upon analytical results or other information compiled by department staff or the department’s designee.
	(4)	The department may assign additional requirements as it deems necessary to protect the public health, including public notification requirements.
	d. 	Analytical methodology for radionuclides. Analysis for the following contaminants shall be conducted to determine compliance with 41.8(1)“b” in accordance with the methods in the following table, or equivalent methods determined in accordance with 567—41.12(455B).
	(1)	Radionuclide Analytical Methodology Table.
RADIONUCLIDE ANALYTICAL METHODOLOGY

 	 	Reference (method or page number)	
Contaminant	Methodology	EPA1	EPA2	EPA3	EPA4	SM5	ASTM6	USGS7	DOE8	Other	
Naturally occurring:	
Gross alpha11 & beta	Evaporation	900.0	p. 1	00-01	p. 1	302, 7110B, 7110 B-00	 	R-1120-76	 	 	
Gross alpha11	Co-precipitation	 	 	00-02	 	7110C, 7110 C-00	 	 	 	 	
Radium-226	Radon emanation	903.1	p. 16	Ra-04	p. 19	305, 7500-Ra C, 7500Ra C-01	D 3454-97, 05	R-1141-76	Ra-04	NY9	
 	Radiochemical	903.0	p. 13	Ra-03	 	304, 7500-Ra B, 7500-Ra B-01	D 2460-97, 07	R-1140-76	 	GA14	
Radium-228	Radiochemical	904.0	p. 24	Ra-05	p. 19	7500-Ra D, 7500-Ra D-01	 	R-1142-76	 	NY9
NJ10
GA14	
Uranium12	Radiochemical	908.0	 	 	 	7500-U B, 7500-U B-00	 	 	 	 	
 	Fluorometric	908.1	 	 	 	7500-U C (17th edition)	D 2907-97	R-1180-76
R-1181-76	U-04	 	
 	ICP-MS	200.813	 	 	 	3125	D 5673-03, 05, 10	 	 	 	
 	Alpha spectrometry	 	 	00-07	p. 33	7500-U C, 7500-U C-00	D 3972-97, 02, 09	R-1182-76	U-02	 	
 	Laser phosphorimetry	 	 	 	 	 	D 5174-97, 02, 07	 	 	 	
 	Alpha liquid scintillation spectrometry	 	 	 	 	 	D 6239-09	 	 	 	
Man-made:	
Radioactive Cesium	Radiochemical	901.0	p. 4	 	 	7500-Cs B, 7500-Cs B-00	D 2459-72	R-1111-76	 	 	
 	Gamma ray spectrometry	901.1	 	 	p. 92	7120, 7120-97	D 3649-91, 98a, 06	R-1110-76	4.5.2.3	 	
Radioactive Iodine	Radiochemical	902.0	p. 6
p. 9	 	 	7500-I B, 7500-I B-00
7500-I C, 7500-I C-00
7500-I D, 7500-I D-00	D 3649-91, 98a, 06	 	 	 	
 	Gamma ray spectrometry	901.1	 	 	p. 92	7120, 7120-97	D 4785-93, 00a, 08	 	4.5.2.3	 	
Radioactive
Strontium 89, 90	Radiochemical	905.0	p. 29	Sr-04	p. 65	303, 7500-Sr B, 7500-Sr B-01	 	R-1160-76	Sr-01
Sr-02	 	
Tritium	Liquid scintillation	906.0	p. 34	H-02	p. 87	306, 7500-3H B, 7500-3H B-00	D 4107-91, 98 (Reapproved 2002), 08	R-1171-76	 	 	
Gamma emitters	Gamma ray spectrometry	901.1
902.0
901.0	 	 	p. 92	7120
7500-Cs B, 7500-Cs B-00
7500-I B, 7500-I B-00	D 3649-91, 98a, 06
D 4785-93, 00a, 08	R-1110-76	Ga-01-R	 	

<fo:wrapper font-size="8pt">The procedures shall be done in accordance with the documents listed below. The incorporation by reference of documents 1 through 10 was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies of the documents may be obtained from the sources listed below. Information regarding obtaining these documents can be obtained from the Safe Drinking Water Hotline at (800)426-4791. Documents may be inspected at EPA’s Drinking Water Docket, EPA West, 1301 Constitution Avenue, NW, Room B135, Washington, DC 20460 (telephone (202)566-2426); or at the Office of Federal Register, 800 North Capitol Street, NW, Suite 700, Washington, DC.</fo:wrapper>	
1“Prescribed Procedures for Measurement of Radioactivity in Drinking Water,” EPA 600/4-80-032, August 1980. Available at the US Department of Commerce, NTIS, 5285 Port Royal Road, Springfield, VA 22161 (telephone (800)553-6847) PB 80-224744.
2“Interim Radiochemical Methodology for Drinking Water,” EPA 600/4-75-008(revised), March 1976. Available at NTIS, ibid.	PB 253258.
3“Radiochemistry Procedures Manual,” EPA 520/5-84-006, December 1987. Available at NTIS, ibid.	PB 84-215581.
4“Radiochemical Analytical Procedures for Analysis of Environmental Samples,” March 1979. Available at NTIS, ibid.	EMSL LV 053917.
5Standard Methods for the Examination of Water and Wastewater, 13th, 17th, 18th, 19th, 20th, 21st, and 22nd editions, 1971, 1989, 1992, 1995, 1998, 2005, and 2012. Available at American Public Health Association, 800 I Street, NW, Washington, DC 20001-3710. Methods 302, 303, 304, 305, and 306 are only in the 13th edition. Methods 7110B, 7500-Ra B, 7500-Ra C, 7500-Ra D, 7500-U B, 7500-Cs B, 7500-I B, 7500-I C, 7500-I D, 7500-Sr B, 7500-3H B are in the 17th, 18th, 19th, 20th, 21st, and 22nd editions. Method 7110C and Method 7500-U C Alpha spectrometry are in the 18th, 19th, 20th, 21st, and 22nd editions. Method 7500-U C Fluorimetric Uranium is only in the 17th and 21st editions. Method 7120 is only in the 19th, 20th, 21st, and 22nd editions. Method 3125 is only in the 20th edition. Methods 7110 B-00, 7110 C-00, 7500-Ra B-01, 7500-Ra C-01, 7500-Ra D-01, 7500-U B-00, 7500-U C-00, 7500-I B-00, 7500-I C-00, 7500-I D-00, 7120-97, 7500-Sr B-01, and 7500-3H B-00 are available online at www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only online versions that may be used.
6Annual Book of ASTM Standards, Volumes 11.01 and 11.02, 2002. Any year containing the cited version of the method may be used. Available at ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428.
7“Methods for Determination of Radioactive Substances in Water and Fluvial Sediments,” Chapter A5 in Book 5 of Techniques of Water-Resources Investigations of the United States Geological Survey, 1977. Available at U.S. Geological Survey (USGS) Information Services, Box 25286, Federal Center, Denver, CO 80225-0425.
8“EML Procedures Manual,” 28th (1997) or 27th (1990) edition, Volumes 1 and 2; either edition may be used. In the 27th edition, Method Ra-04 is listed as Ra-05, and Method Ga-01-R is listed as Sect. 4.5.2.3. Available at the Environmental Measurements Laboratory, U.S. Department of Energy (DOE), 376 Hudson Street, New York, NY 10014-3621.
9“Determination of Ra-226 and Ra-228 (Ra-02),” January 1980, revised June 1982. Available at Radiological Sciences Institute Center for Laboratories and Research, New York State Department of Health, Empire State Plaza, Albany, NY 12201.
10“Determination of Radium-228 in Drinking Water,” August 1980. Available at State of New Jersey, Department of Environmental Protection, Division of Environmental Quality, Bureau of Radiation and Inorganic Analytical Services, 9 Ewing Street, Trenton, NJ 08625.
11Natural uranium and thorium-230 are approved as gross alpha calibration standards for gross alpha with co-precipitation and evaporation methods; americium-241 is approved with co-precipitation methods.
12If uranium (U) is determined by mass, a 0.67 pCi/μg of uranium conversion factor must be used. This conversion factor is based on the 1:1 activity ratio of U-234 to U-238 that is characteristic of naturally occurring uranium.
13“Determination of Trace Elements in Waters and Wastes by Inductively Coupled Plasma-Mass Spectrometry,” Revision 5.4, which is published in “Methods for the Determination of Metals in Environmental Samples – Supplement 1,” EPA 600-R-94-111, May 1994. Available at NTIS, PB 95-125472.
14“The Determination of Radium-226 and Radium-228 in Drinking Water by Gamma-Ray Spectrometry Using HPGW or Ge(Li) Detectors,” Revision 1.2, December 2004. Available from Environmental Resources Center, Georgia Institute of Technology, 620 Cherry Street, Atlanta, GA 30332-0335; telephone: (404)894-3776.
	(2)	Method references for other radionuclides. When the identification and measurement of radionuclides other than those listed in 41.8(1)“b” are required, the following references are to be used, except in cases where alternative methods have been approved in accordance with 567—41.12(455B).
	1.	“Procedures for Radiochemical Analysis of Nuclear Reactor Aqueous Solutions,” H. L. Krieger and S. Gold, EPA-R4-73-014, Environmental Protection Agency, Cincinnati, Ohio 45268 (May 1973).
	2.	“HASL Procedure Manual,” edited by John H. Harley. HASL 300, ERDA Health and Safety Laboratory, New York, NY (1973).
	e. 	Monitoring requirements for gross alpha, radium-226, radium-228, and uranium.
	(1)	General requirements.
	1.	Monitoring frequency and confirmation samples. The department may require more frequent monitoring than specified in this paragraph. The department may require confirmation samples at its discretion. The results of the initial and confirmation samples will be averaged for use in compliance determinations.
	2.	Monitoring period. Each PWS shall monitor during the time period designated by the department in the operation permit.
	(2)	Applicability and sampling locations.
	1.	Existing systems and sources. All existing CWSs must sample at every entry point to the distribution system that is representative of all sources being used under normal operating conditions. The system must take each sample at the same source/entry sampling point, unless conditions make another alternate sampling point more representative of each source, or the department has designated a distribution system location, in accordance with 41.8(1)“e”(3)“4.” The department must approve any alternate sampling point for radionuclides.
	2.	New systems and sources. All new CWSs or CWSs that use a new source of water must begin to conduct initial monitoring for the new system or source within the first calendar quarter after initiating use of the system or source. More frequent monitoring must be conducted by the CWS when required by the department, in the event of possible contamination or when changes in the distribution system or treatment processes occur which may increase the concentration of radioactivity in finished water.
	(3)	Initial monitoring. Systems must conduct initial monitoring for gross alpha particle activity, radium-226, radium-228, and uranium as follows. If the average of the initial monitoring results for a source/entry point is above the MCL, the system must collect and analyze quarterly samples at that source/entry point until the system has results from four consecutive quarters that are at or below the MCL, unless the system enters into another schedule as part of a formal compliance agreement with the department.
	1.	Systems without historical monitoring data. Systems without historical monitoring data must collect four consecutive quarterly samples at all source/entry sampling points before December 31, 2007. The department may waive the final two quarters of initial monitoring from a source/entry point if the results of the samples from the previous two quarters are below the detection limit.
	2.	Systems with historical monitoring data and one source/entry point. Systems with only one source/entry point may use historical monitoring data collected between January 1, 2000, and December 31, 2003, from either the representative point in the distribution system or the source/entry point to satisfy the initial monitoring requirement.
	3.	Systems with historical source/entry point monitoring data and multiple source/entry points. Systems with multiple source/entry points that also have appropriate historical monitoring data for each source/entry point may use the monitoring data collected between January 1, 2000, and December 31, 2003, to satisfy the initial monitoring requirement.
	4.	Systems with historical distribution system monitoring data and multiple source/entry points. Systems with appropriate historical data for a representative point in the distribution system and multiple source/entry points may use the monitoring data collected between January 1, 2000, and December 31, 2003, provided that the department determines that the historical data satisfactorily demonstrates that each source/entry point is expected to be in compliance based upon the historical data and reasonable assumptions about the variability of contaminant levels between source/entry points. The department must make a written finding indicating how the data conforms to these requirements, in order for the data to satisfy the initial monitoring requirements.
	(4)	Reduced monitoring. The department may allow a CWS to reduce the future frequency of monitoring from once every three years to once every six or nine years at each source/entry point, based on the following criteria. The samples collected during the reduced monitoring period must be used to determine the monitoring frequency for subsequent monitoring periods (e.g., if a system’s source/entry point is on a nine-year frequency, and the sample result is above half of the MCL, then the next monitoring frequency for that source/entry point is three years). If a system has a monitoring result that exceeds the MCL while on reduced monitoring, the system must collect and analyze quarterly samples at that source/entry point until the system has results from four consecutive quarters that are below the MCL, unless the system enters into another schedule as part of a formal compliance agreement with the department.
	1.	Nine-year frequency. If the average of the initial monitoring results for each contaminant is below the detection limit specified in 41.8(1)“c”(1)“2,” the system must collect and analyze for that contaminant using at least one sample at that source/entry point every nine years.
	2.	Six-year frequency. If the average of the initial monitoring results for gross alpha particle activity, uranium, and combined radium-226 and radium-228 is at or above the detection limit and at or below half the MCL for that contaminant, the system must collect and analyze for that contaminant using at least one sample at that source/entry point every six years. The analytical results for radium-226 and radium-228 must be added together to yield the combined result.
	3.	Three-year frequency. If the average of the initial monitoring results for gross alpha particle activity, uranium, and combined radium-226 and radium-228 is above half of the MCL and at or below the MCL for that contaminant, the system must collect and analyze for that contaminant using at least one sample at that source/entry point every three years. The analytical results for radium-226 and radium-228 must be added together to yield the combined result.
	(5)	Composite samples. To fulfill quarterly monitoring requirements for gross alpha particle activity, radium-226, radium-228, or uranium, a system may composite up to four consecutive quarterly samples from a single entry point if analysis is done within one year of the first sample. The analytical results from the composited samples will be considered by the department as the average analytical result to determine compliance with the MCLs and to determine the future monitoring frequency. If the analytical result from the composited sample is greater than half of the MCL, the department may require additional quarterly samples from the system before the system will be allowed to sample under a reduced monitoring schedule.
	(6)	Data substitution using gross alpha particle activity results.
	1.	A gross alpha particle activity measurement may be substituted for the required uranium measurement provided that the measured gross alpha particle activity does not exceed 15 pCi/L.
	2.	The gross alpha particle activity measurement shall have a confidence interval of 95 percent (1.65 sigma, where sigma is the standard deviation of the net counting rate of the sample) for uranium. When a system uses a gross alpha particle activity measurement in lieu of a uranium measurement, the gross alpha particle activity analytical result will be used to determine the future monitoring frequency for uranium. If the gross alpha particle activity result is less than the detection limit, half the detection limit will be used to determine compliance and the future monitoring frequency.
	f. 	Monitoring requirements for beta particle and photon emitters. To determine compliance with the maximum contaminant levels in 41.8(1)“b”(2) for beta particle and photon radioactivity, a system must monitor at a frequency specified in 41.8(1)“f.”
	(1)	General requirements.
	1.	Monitoring frequency and confirmation samples. The department may require more frequent monitoring than specified in 41.8(1)“f.” The department may require confirmation samples at its discretion. The results of the initial and confirmation samples will be averaged for use in compliance determinations.
	2.	Monitoring period. Each PWS shall monitor during the time period designated by the department in the operation permit.
	(2)	Systems designated by the department as vulnerable to man-made radioactivity.
	1.	Initial monitoring. Systems that have been determined by the department to be vulnerable to man-made radioactivity must collect quarterly samples for beta emitters and annual samples for tritium and strontium-90 at each entry point to the distribution system, beginning within one quarter after being notified by the department of this requirement. Systems already required to conduct beta particle and photon radioactivity monitoring must continue to sample until the department removes the monitoring requirement.
	2.	Reduced monitoring. The department may reduce the frequency of monitoring at that sampling point to once every three years, if the gross beta particle activity minus the naturally occurring potassium-40 beta particle activity at a source/entry point has a running annual average (computed quarterly) of less than or equal to 50 pCi/L (screening level). Systems must collect all of the samples required in 41.8(1)“f”(2)“1” during the reduced monitoring period.
	3.	Data substitution. For a system in the vicinity of a nuclear facility, the department may allow the system to utilize environmental surveillance data collected by the nuclear facility in lieu of monitoring at the system’s source/entry point(s), where the department determines such data is applicable to a particular water system. In the event that there is a release from a nuclear facility, systems which are using surveillance data must begin monitoring at the system’s source/entry point(s) in accordance with 41.8(1)“f”(2).
	(3)	Systems determined to utilize waters contaminated by effluents from nuclear facilities.
	1.	Initial monitoring. Systems designated by the department as utilizing water contaminated by effluents from nuclear facilities must sample for beta particle and photon radioactivity. Systems must collect quarterly samples for beta emitters and iodine-131 and annual samples for tritium and strontium-90 at each entry point to the distribution system, beginning within one quarter after being notified by the department. Systems already designated by the department as systems using waters contaminated by effluents from nuclear facilities must continue to sample until the department removes the sampling requirement.
	●	Gross beta particle activity. Quarterly monitoring for gross beta particle activity shall be based on the analysis of monthly samples or the analysis of a composite of three monthly samples. The former is recommended.
	●	Iodine-131. A composite of five consecutive daily samples shall be analyzed once each quarter for iodine-131. The department may require more frequent monitoring when iodine-131 is identified in the finished water.
	●	Strontium-90 and tritium. Annual monitoring for strontium-90 and tritium shall be conducted by means of the analysis of a composite of four consecutive quarterly samples or analysis of four quarterly samples. The latter procedure is recommended.
	2.	Reduced monitoring. If the gross beta particle activity minus the naturally occurring potassium-40 beta particle activity at a sampling point has a running annual average (computed quarterly) less than or equal to 15 pCi/L (screening level), the department may reduce the frequency of monitoring at that sampling point to every three years. Systems must collect all samples required in 41.8(1)“f”(3) during the reduced monitoring period.
	3.	Data substitution. For systems in the vicinity of a nuclear facility, the department may allow the CWS to utilize environmental surveillance data collected by the nuclear facility in lieu of monitoring at the system’s entry point(s), where the department determines such data is applicable to a particular water system. In the event that there is a release from a nuclear facility, systems which are using surveillance data must begin monitoring at the CWS source/entry point in accordance with 41.8(1)“f”(2)“1.”
	(4)	Monitoring frequency waiver. A CWS designated by the department to monitor for beta particle and photon radioactivity cannot apply to the department for a waiver from the monitoring frequencies specified in 41.8(1)“f”(2) or (3).
	(5)	Community water systems may analyze for naturally occurring potassium-40 beta particle activity from the same or an equivalent sample used for the gross beta particle activity analysis. Systems are allowed to subtract the potassium-40 beta particle activity value from the total gross beta particle activity value to determine if the screening level is exceeded. The potassium-40 beta particle activity must be calculated by multiplying elemental potassium concentrations (in mg/L) by a factor of 0.82.
	(6)	If the gross beta particle activity minus the naturally occurring potassium-40 beta particle activity exceeds the appropriate screening level, an analysis of the sample must be performed to identify the major radioactive constituents present in the sample, and the appropriate doses must be calculated and summed to determine compliance with 41.8(1)“b”(2)“1,” using the formula in 41.8(1)“b”(2)“2.” Doses must also be calculated and combined for measured levels of tritium and strontium to determine compliance.
	(7)	Monitoring after an MCL violation. Systems must monitor monthly at the sampling point(s) which exceed the maximum contaminant level in 41.8(1)“b”(2) beginning the month after the exceedance occurs. Systems must continue monthly monitoring until the system has established, by a rolling average of three monthly samples, that the MCL is being met. Systems that establish that the MCL is being met must return to quarterly monitoring until they meet the requirements set forth in 41.8(1)“f”(2) or 41.8(1)“f”(3)“2.”
	41.8(2) Reserved.
[ARC 9915B, IAB 12/14/11, effective 1/18/12; ARC 3735C, IAB 4/11/18, effective 5/16/18]
567—41.9(455B) Sampling and analytical requirements for radionuclides. Rescinded IAB 1/7/04, effective 2/11/04.
567—41.10(455B) Reporting, public notification and record keeping. Rescinded IAB 8/11/99, effective 9/15/99.
567—41.11(455B) Special monitoring.
	41.11(1) Special monitoring for sodium. Suppliers of water for community public water systems shall collect and have analyzed one sample per source or plant, for the purpose of determining the sodium concentration in the distribution system. Systems utilizing multiple wells that draw raw water from a single aquifer may, with departmental approval, be considered as one source for determining the minimum number of samples to be collected. Sampling frequency and approved analytical methods are as follows:
	a. 	Surface water systems. Systems utilizing a surface water source, in whole or in part, shall monitor for sodium at least once annually at the entry point to the distribution system.
	b. 	Groundwater systems. Systems utilizing groundwater sources shall monitor at least once every three years at the entry point to the distribution system.
	c. 	Increased monitoring. Suppliers may be required to monitor more frequently where sodium levels are variable or if certain types of treatment are used, such as cation exchange softening.
	d. 	Analytical methodology. Analyses for sodium shall be performed in accordance with 41.3(1)“e”(1).
	e. 	Reporting. The sodium level shall be reported to the public by at least one of the following methods:
	(1)	The community public water supply shall notify the appropriate local public health officials of the sodium levels by written notice by direct mail within three months of receipt of the analytical results. A copy of each notice required by this subrule shall be sent to the department within ten days of its issuance.
	(2)	In lieu of the reporting requirement of 41.11(1)“e”(1), the community public water supply shall include the sodium level in its annual consumer confidence report, pursuant to 567—paragraph 42.3(3)“c”(1)“12.”
	f. 	CWSs using cation exchange treatment. Community water systems which utilize cation exchange treatment are required to collect one sodium sample of the finished water per year after all treatment. Analysis and reporting must be done in accordance with 41.11(1)“d” and “e.”
	41.11(2) Special monitoring for ammonia. Ammonia in the groundwater is a precursor to the development of nitrite and nitrate in a drinking water system. Both nitrite and nitrate are contaminants with acute health effects. This subrule lists the ammonia analytical methodology, sample preservation requirements, and holding times to be used for drinking water samples.
	a. 	Analytical methodology. Analyses for ammonia shall be performed in accordance with the following methodology, with a detection limit of 0.1 mg/L ammonia as N:

Methodology	EPA1	Standard Methods
(20th edition)	ASTM	USGS2	Other	
Manual distillation at pH 9.54, followed by:	350.2	4500-NH3 B	 	 	973.493	
Titration	350.2	4500-NH3 C	 	 	 	
Manual electrode	350.3	4500-NH3 D or E	D1426-93(B)	 	 	
Automated phenate	350.1	4500-NH3 G	 	I-4523-85	 	
Automated electrode	 	 	 	 	See note5	
1“Methods for Chemical Analysis of Water and Wastes,” Environmental Protection Agency, EPA-600/4-79-020, Revised March 1983 and 1979 where applicable.
2Fishman, M.J., et al., “Methods for Analysis of Inorganic Substances in Water and Fluvial Sediments,’’ U.S. Department of the Interior, Techniques of Water—Resource Investigations of the U.S. Geological Survey, Denver, CO, Revised 1989, unless otherwise stated.
3“Official Methods of Analysis of the Association of Official Analytical Chemists,” 15th edition, 1990.
4Manual distillation is not required if the samples are very low in turbidity; however, manual distillation should be used whenever matrix interferences could be present in the sample, and will be required to resolve any controversies.
5Ammonia, Automated Electrode Method, Industrial Method Number 379-75 WE, dated February 19, 1976, Bran & Luebbe (Technicon) Auto Analyzer II, Bran & Luebbe Analyzing Technologies, Inc., Elmsford, NY 10523.
	b. 	Sample preservation and holding time. The system must collect a 500 mL grab sample into a plastic or glass bottle. The sample must be acidified at the time of collection to a pH of less than 2 by the addition of sulfuric acid (H2SO4) and refrigerated at 4 degrees Celsius. The sample must be analyzed within 28 days. If the sample is analyzed within 24 hours of collection, the sample acidification is not required.
567—41.12(455B) Alternative analytical techniques. With the written permission of this department, concurred in by the EPA, an alternative analytical technique may be employed. An alternative technique shall be acceptable only if it is substantially equivalent to the prescribed test in both precision and accuracy as it relates to the determination of compliance with any maximum contaminant level. The use of the alternative analytical technique shall not decrease the frequency of monitoring required by 567—41.2(455B) through 567—41.8(455B).
567—41.13(455B) Monitoring of interconnected public water supply systems. When a public water supply system supplies water to one or more other public water supply systems, the department may modify the monitoring requirements imposed by this part to the extent that the interconnection of the systems justifies treating them as a single system for monitoring purposes. Any modified monitoring shall be conducted pursuant to a schedule specified by the department and concurred in by the administrator of the U.S. Environmental Protection Agency.
567—41.14(455B) Department analytical results used to determine compliance. Analytical results or other information compiled by departmental staff may be used to determine compliance with the maximum contaminant levels, action levels, or treatment techniques listed in 567—Chapters 41 and 43 or for initiating remedial action with respect to these violations.
567—41.15(455B) Monitoring of other contaminants. If the department determines that other contaminants are present in a public water supply, and the contaminants are known to pose, or scientific evidence strongly suggests that they pose, a threat to human health, the supplier of water may be required to monitor for such contaminants. The supplier of water will monitor at a frequency and in a manner which will adequately identify the magnitude and extent of the contamination. The monitoring frequency and sampling location will be determined by the department. All analytical results will be obtained using approved EPA methods and all analytical results will be submitted to the department for review and evaluation. Any monitoring required under this paragraph will be incorporated into an operation permit or an order.
These rules are intended to implement Iowa Code sections 455B.171 through 455B.188 and 455B.190 through 455B.192.
[Filed prior to 7/1/52; amended 7/31/74]
[Filed 3/5/76, Notice 12/1/75—published 3/22/76, effective 4/26/76]
[Filed 2/25/77, Notice 11/17/76—published 3/23/77, effective 6/24/77]
[Filed without Notice 4/28/77—published 5/18/77, effective 6/24/77]
[Filed 7/1/77, Notice 3/23/77—published 7/27/77, effective 8/31/77]
[Filed after Notice 5/25/78, Notice 12/28/77, 5/3/78—published 6/14/78, effective 5/25/78]
[Filed 10/13/78, Notice 5/3/78—published 11/1/78, effective 12/6/78]
[Filed 2/2/79, Notice 7/26/78—published 2/21/79, effective 3/28/79]
[Filed 3/30/79, Notice 2/7/79—published 4/18/79, effective 5/23/79]
[Filed 5/11/79, Notice 2/7/79—published 5/30/79, effective 7/5/79]
[Filed 1/4/80, Notice 9/5/79—published 1/23/80, effective 2/27/80]
[Filed 6/6/80, Notice 3/19/80—published 6/25/80, effective 7/30/80]
[Filed 4/23/81, Notice 2/18/81—published 5/13/81, effective 6/17/81]
[Filed 6/18/82, Notice 4/14/82—published 7/7/82, effective 8/11/82]
[Filed emergency 6/3/83—published 6/22/83, effective 7/1/83]
[Filed 12/2/83, Notice 6/22/83—published 12/21/83, effective 1/25/84]
[Filed 3/22/85, Notice 9/12/84—published 4/10/85, effective 5/15/85]
[Filed emergency 11/14/86—published 12/3/86, effective 12/3/86]
[Filed 8/21/87, Notice 6/17/87—published 9/9/87, effective 10/14/87]
[Filed emergency 10/2/87—published 10/21/87, effective 10/14/87]
[Filed 7/22/88, Notice 5/18/88—published 8/10/88, effective 9/14/88]
[Filed 1/19/90, Notice 9/20/89—published 2/7/90, effective 3/14/90]
[Filed 11/26/90, Notice 6/13/90—published 12/12/90, effective 1/16/91]◊
[Filed 9/25/92, Notice 6/10/92—published 10/14/92, effective 11/18/92]
[Filed 7/30/93, Notice 5/12/93—published 8/18/93, effective 9/22/93]
[Filed 9/24/93, Notice 5/12/93—published 10/13/93, effective 11/17/93]1
[Filed 3/22/96, Notice 11/8/95—published 4/10/96, effective 5/15/96]
[Filed 7/23/99, Notice 4/7/99—published 8/11/99, effective 9/15/99]
[Filed 9/29/00, Notice 6/14/00—published 10/18/00, effective 11/22/00]
[Filed 12/17/03, Notice 9/17/03—published 1/7/04, effective 2/11/04]
[Filed ARC 9915B (Notice ARC 9737B, IAB 9/7/11), IAB 12/14/11, effective 1/18/12]
[Filed ARC 3735C (Notice ARC 3568C, IAB 1/17/18), IAB 4/11/18, effective 5/16/18]
◊	Two or more ARCs
1	Effective date of [ARC4359A] 41.3(1)“b”(2)“3”; 41.3(1)“c”(2)“4,” new sentence at end; 41.3(1)“c”(3)“6,” “10”; 41.3(1)“c”(8), first sentence; 41.4(1)“d”(5)“4”; 41.5(1)“a”; 41.10(7)“a”(3); 41.11(2)“a”; 41.11(2)“c”(4); 41.11(2)“c”(5), first sentence, delayed 70 days by the Administrative Rules Review Committee at its meeting held November 9, 1993; delay lifted by the Committee December 14, 1993.