CHAPTER 25
STATE PLUMBING CODE
[Prior to 7/29/87, see Health Department[470] Ch 25]
641—25.1(105) Adoption. Sections 101 and 102 and Chapters 2 to 17 of the Uniform Plumbing Code, 2015 Edition, as published by the International Association of Plumbing and Mechanical Officials, 4755 E. Philadelphia Street, Ontario, California 91761-2816, are hereby adopted by reference with amendments as the state plumbing code authorized by Iowa Code section 105.4. Portions of this chapter reproduce excerpts from the 2015 International Plumbing Code; Copyright 2014; Washington, D.C.: International Code Council. Such excerpts are reproduced with permission, all rights reserved. www.ICCSAFE.org
[ARC 8860B, IAB 6/16/10, effective 7/21/10; ARC 1089C, IAB 10/16/13, effective 11/20/13; ARC 2474C, IAB 3/30/16, effective 6/1/16; ARC 3062C, IAB 5/10/17, effective 6/14/17]
641—25.2(105) Applicability. The provisions of this code are applicable to the plumbing in buildings or on premises in Iowa.
[ARC 8860B, IAB 6/16/10, effective 7/21/10]
641—25.3(105) Fuel gas piping. Fuel gas piping shall comply with the requirements of Chapter 12 of the Uniform Plumbing Code, 2015 Edition, unless the provisions conflict with 661—Chapter 226, Liquefied Petroleum Gas, Iowa Administrative Code. Where Chapter 12 conflicts with 661—Chapter 226, the provisions of 661—Chapter 226 shall be followed.
[ARC 8860B, IAB 6/16/10, effective 7/21/10; ARC 1089C, IAB 10/16/13, effective 11/20/13; ARC 2474C, IAB 3/30/16, effective 6/1/16]
641—25.4(105) Amendments to Uniform Plumbing Code. The Uniform Plumbing Code (UPC), as adopted by reference in rule 641—25.1(105), shall be amended as follows:
	25.4(1) Rescinded IAB 5/10/17, effective 6/14/17.
	25.4(2) The following amendments shall apply to UPC Chapter 3:
	a. 	Subsection 301.5.1 Permit Application. Delete the subsection.
	b. 	Subsection 314.4.1 Installation of Thermoplastic Pipe and Fittings. Trench width for thermoplastic pipe shall be limited to six times the outside diameter of the piping at the base. Thermoplastic piping shall be bedded in not less than 4 inches (102 mm) of aggregate bedding material supporting the pipe. Initial backfill shall encompass the pipe. Aggregate material shall be three-eighths (3/8) inch p-gravel or 1-inch clean class one bedding.
	25.4(3) The following amendments shall apply to UPC Chapter 4:
a	The fixtures shown are based on one fixture being the minimum required for the number of persons indicated or any fraction of the number of persons indicated. The number of occupants shall be determined by the International Building Code.
b	Toilet facilities for employees shall be separate from facilities for inmates or care recipients.
c	A single-occupant toilet room with one water closet and one lavatory serving not more than two adjacent patient sleeping units shall be permitted provided that each patient sleeping unit has direct access to the toilet room and provision for privacy for the toilet room user is provided.
d	The occupant load for seasonal outdoor seating and entertainment areas shall be included when determining the minimum number of facilities required.
e	For business and mercantile occupancies with an occupant load of 15 or fewer, service sinks shall not be required.
*Excerpted (with modifications) from Table 403.1 of the 2015 International Plumbing Code; Copyright 2014; Washington, D.C.: International Code Council. Reproduced with permission. All rights reserved. www.ICCSAFE.org
	j. 	Subsection 422.2.1 Family or Assisted-Use Toilet and Bathing Facilities. Modify the subsection by adding the following sentence to the end of the subsection: “Required family or assisted-use fixtures are permitted to be included in the number of required fixtures for either the male or female occupants in assembly and mercantile occupancies.”
	k. 	Insert the following text at the end of Chapter 4:
“422.6 Pay Facilities. Where pay facilities are installed and permissible under Iowa law, such facilities shall be in excess of the required minimum facilities. Required facilities shall be free of charge.
“422.7 Substitution for Water Closets. In each bathroom or toilet room, urinals shall not be substituted for more than 67 percent of the required water closets in assembly and educational occupancies. Urinals shall not be substituted for more than 50 percent of the required water closets in all other occupancies. (Reprinted from the 2015 International Plumbing Code section 419.2)”
	25.4(4) The following amendment shall apply to UPC Chapter 5:
Sections 503.0 through 503.2 Inspection. Delete the sections.
	25.4(5) The following amendments shall apply to UPC Chapter 6:
	a. 	Section 603.4.8 Drain Lines. Modify the section by adding the following language to the end of the section: “or in accordance with the manufacturer’s drain-sizing chart for installation.”
	b. 	Section 609.11 Pipe Insulation. Delete sections 609.11 through 609.11.2 and insert the following in lieu thereof:
Section 609.11 Pipe Insulation. Insulation of domestic hot water piping shall be in accordance with the applicable energy conservation code.
	c. 	Section 611.4 Sizing of Residential Softeners. Modify the section by adding the following to the end of the last sentence in the section: “or as specified in the manufacturer’s installation instructions.”
	d. 	Section 612 Residential Fire Sprinkler Systems. Delete sections 612.0 through 612.7.2.
	25.4(6) The following amendment shall apply to UPC Chapter 7:
Section 710.1 Backflow Protection. Modify the section by adding the following sentences to the end of the section: “The requirement for the installation of a backwater valve shall apply only when determined necessary by the authority having jurisdiction based on local conditions. When a valve is required by the authority having jurisdiction, it shall be a manually operated gate valve or fullway ball valve. An automatic backwater valve may also be installed but is not required.”
	25.4(7) The following amendment shall apply to UPC Chapter 8:
Section 807.3 Domestic Dishwashing Machine. Modify the section by deleting the section and inserting the following language in lieu thereof: “No domestic dishwashing machine shall be directly connected to a drainage system or food waste disposer without the use of an approved dishwasher air gap fitting on the discharge side of the dishwashing machine, or by looping the discharge line of the dishwasher as high as possible near the flood level of the kitchen sink where the waste disposer is connected. Listed air gap fittings shall be installed with the flood level (FL) marking at or above the flood level of the sink or drainboard, whichever is higher.”
	25.4(8) The following amendment shall apply to UPC Chapter 9:
	a. 	Section 906.7 Frost or Snow Closure. Modify the section by deleting “two (2) inches (50.8 mm)” in the first sentence and inserting “three (3) inches (76.2 mm)” in lieu thereof.
	b. 	Section 908.2.2 Size. Delete the second sentence in this section and insert the following new sentence in lieu thereof: “The wet vent shall be not less than 2 inches (50 mm) in diameter for 6 drainage fixture units (dfu) or less, and not less than 3 inches (80 mm) in diameter for 7 dfu or more.”
	25.4(9) The following amendment shall apply to UPC Chapter 10:
	a. 	Table 1002.2 Horizontal Lengths of Trap Arms. Delete the table and insert the following table in lieu thereof:

TABLE 1002.2
Horizontal Lengths of Trap Arms
(Except for Water Closets and Similar Features)<fo:wrapper font-size=".69em" baseline-shift=".33em">1,2</fo:wrapper>	
Trap Arm Diameter (inches)	Distance Trap to Vent
Minimum (inches)	Length Maximum (feet)	
1¼	2½	5	
1½	3	6	
2	4	8	
3	6	12	
4	8	12	
Exceeding 4	2 × Diameter	12	
<fo:wrapper font-size="8pt">For SI units: 1 inch = 25.4 mm</fo:wrapper>
<fo:wrapper font-size="8pt">Notes:</fo:wrapper>
<fo:wrapper font-size=".69em" baseline-shift=".33em">1</fo:wrapper><fo:wrapper font-size="8pt">Maintain ¼ inch per foot slope (20.8 mm/m).</fo:wrapper>
<fo:wrapper font-size=".69em" baseline-shift=".33em">2</fo:wrapper><fo:wrapper font-size="8pt">The developed length between the trap of a water closet or similar fixture (measured from the top of the closet flange to the inner edge of the vent) and its vent shall not exceed 6 feet (1829 mm).</fo:wrapper>	
	b. 	Section 1014.1.3 Food Waste Disposers and Dishwashers. Modify the section by deleting the second sentence and inserting the following in lieu thereof: “Commercial food waste disposers shall discharge into the building’s drainage system in accordance with the requirements of the Authority Having Jurisdiction.”
	25.4(10) The following amendments shall apply to UPC Chapter 12:
	a. 	Sections 1203.0 through 1203.4 Inspection. Delete the sections.
	b. 	Sections 1204.0 through 1204.3 Certificate of Inspection. Delete the sections.
	c. 	Sections 1205.0 through 1205.2 Authority to Render Gas Service. Delete the sections.
	d. 	Sections 1207.0 and 1207.1 Temporary Use of Gas. Delete the sections.
	25.4(11) The following amendments shall apply to UPC Chapter 13:
	a. 	Sections 1304.5 through 1304.5.3 Construction Documents. Delete the sections.
	b. 	Section 1320.3 Report Items. Modify the section by deleting “Authority Having Jurisdiction” and inserting “responsible facility authority” in lieu thereof.
	25.4(12) The following amendment shall apply to UPC Chapter 14:
Sections 1406.0 through 1406.4 Required Inspection. Delete the sections.
	25.4(13) The following amendments shall apply to UPC Chapter 15:
	a. 	Section 1501.3 Permit. Delete the section.
	b. 	Section 1501.6 Operation and Maintenance Manual. Modify the section by deleting “required to have a permit in accordance with Section 1501.3” from the first sentence.
	c. 	Subsection 1501.11.2.1 Visual System Inspection. Modify the subsection by deleting “by the Authority Having Jurisdiction and other authorities having jurisdiction” from the first sentence.
	d. 	Subsection 1501.11.2.2 Cross-Connection Test. Modify the subsection by deleting “by the applicant in the presence of the Authority Having Jurisdiction and other authorities having jurisdiction” from the first sentence.
	e. 	Subsection 1501.11.2.3 Discovery of Cross-Connection. Modify the subsection by deleting “in the presence of the Authority Having Jurisdiction.”
	f. 	Section 1503.2 Permit. Delete the section.
	g. 	Section 1504.2 Plumbing Plan Submission. Delete the section.
	h. 	Section 1504.5 Initial Cross-Connection Test. Modify the section by deleting “by the applicant in the presence of the Authority Having Jurisdiction and other authorities having jurisdiction,” and by deleting the final sentence (“The test shall be ruled successful by the Authority Having Jurisdiction before final approval is granted.”).
	25.4(14) The following amendments shall apply to UPC Chapter 16:
	a. 	Section 1602.2 Plumbing Plan Submission. Delete the section.
	b. 	Section 1602.5 Initial Cross-Connection Test. Modify the section by deleting the second and third sentences (“Before the building is occupied or the system is activated, the installer shall perform the initial cross-connection test in the presence of the Authority Having Jurisdiction and other authorities having jurisdiction. The test shall be ruled successful by the Authority Having Jurisdiction before final approval is granted.”).
	c. 	Subsection 1602.11.2.1 Visual System Inspection. Modify the subsection by deleting “by the Authority Having Jurisdiction and other authorities having jurisdiction.”
	d. 	Subsection 1602.11.2.2 Cross-Connection Test. Modify the subsection by deleting “by the applicant in the presence of the Authority Having Jurisdiction and other authorities having jurisdiction.”
	e. 	Subsection 1602.11.2.3 Discovery of Cross-Connection. Modify the subsection by deleting “in the presence of the Authority Having Jurisdiction.”
[ARC 8860B, IAB 6/16/10, effective 7/21/10; ARC 1089C, IAB 10/16/13, effective 11/20/13; ARC 2474C, IAB 3/30/16, effective 6/1/16; ARC 3062C, IAB 5/10/17, effective 6/14/17]
641—25.5(105) Backflow prevention with containment. Cities with populations of 15,000 or greater as determined by the 2010 census or any subsequent regular or special census shall have a backflow prevention program with containment. The minimum requirements for a program are given in subrules 25.5(1) through 25.5(5). These requirements are in addition to the applicable requirements of Section 603 of the Uniform Plumbing Code, 2015 Edition.
	25.5(1) Definitions. The following definitions are added to those in Chapter 2 and Section 603 of the Uniform Plumbing Code, 2015 Edition, or are modified from those definitions for the purposes of rule 641—25.5(105) only.
	a. 	Administrative authority. The administrative authority for this rule is the city council and its designees or, with respect to private water utilities, the Iowa utilities board.
	b. 	Approved backflow prevention assembly for containment. Approved backflow prevention assembly for containment means a backflow prevention assembly which is approved by the University of Southern California Foundation for Cross-Connection Control and Hydraulic Research. The approval listing shall include the limitations of use based on the degree of hazard. The backflow prevention assembly shall also be listed by the International Association of Plumbing and Mechanical Officials (IAPMO) or by the American Society of Sanitary Engineering (ASSE) as having met the requirements of one of the standards listed below.

Standard	Product Covered	
ANSI¤/ASSE* 1013-2009	Reduced Pressure Principle Backflow Preventers	
ANSI¤/ASSE* 1015-2009	Double Check Backflow Prevention Assembly	
ANSI¤/ASSE* 1047-2009	Reduced Pressure Detector Backflow Preventer	
ANSI¤/ASSE* 1048-2009	Double Check Detector Assembly Backflow Preventer	
ANSI¤/AWWA† C510-07	Double Check Valve Backflow Prevention Assembly	
ANSI¤/AWWA† C511-07	Reduced-Pressure Principle Backflow Prevention Assembly	
¤American National Standards Institute, 1819 L Street NW, Washington, DC 20036
*American Society of Sanitary Engineering, 901 Canterbury Road, Suite A, Westlake, OH 44145
†American Water Works Association, 6666 West Quincy Avenue, Denver, CO 80235
	c. 	Approved backflow prevention assembly for containment in a fire protection system. Approved backflow prevention assembly for containment in a fire protection system means a backflow prevention assembly to be used in a fire protection system which meets the requirements of Factory Mutual Research Corporation (FM) and Underwriters Laboratory (UL) in addition to the requirements of 25.5(1)“b.”
	d. 	Containment. Containment is a method of backflow prevention which requires a backflow prevention assembly on certain water services. Containment requires that the backflow prevention assembly be installed on the water service as close to the public water supply main as is practical.
	e. 	Customer. Customer means the owner, operator or occupant of a building or property which has a water service from a public water system, or the owner or operator of a private water system which has a water service from a public water system.
	f. 	Degree of hazard. Degree of hazard means the rating of a cross connection or a water service which indicates if it has the potential to cause contamination (high hazard) or pollution (low hazard).
	g. 	Water service. Depending on the context, water service is the physical connection between a public water system and a customer’s building, property or private water system, or the act of providing potable water from a public water system to a customer.
	25.5(2) Proposed water service.
	a. 	No person shall install, or cause to have installed, a water service to a building, property or private water system before the administrative authority has evaluated the proposed water service for degree of hazard.
	b. 	The administrative authority shall require the submission of plans, specifications and other information deemed necessary for a building, property or private water system to which a water service is proposed. The administrative authority shall review the information submitted to determine if cross connections will exist and the degree of hazard.
	c. 	The owner of a building, property or private water system shall install, or cause to have installed, an approved backflow prevention assembly for containment as directed by the administrative authority before water service is initiated.
	d. 	Reconstruction of an existing water service shall be treated as a proposed water service for the purposes of rule 641—25.5(135).
	25.5(3) Existing water services.
	a. 	Each customer shall survey the activities and processes which receive water from the water service and shall report to the administrative authority if cross connections exist and the degree of hazard.
	b. 	The administrative authority may inspect the plumbing of any building, property and private water system which has a water service to determine if cross connections exist and the degree of hazard.
	c. 	If, based on information provided through 25.5(3)“a” and “b,” the administrative authority determines that a water service may contaminate the public water supply, the administrative authority shall require that the customer install the appropriate backflow prevention assembly for containment.
	d. 	If a customer refuses to install a backflow prevention assembly for containment when it is required by the administrative authority, the administrative authority may order that water service to the customer be discontinued until an appropriate backflow prevention assembly is installed.
	25.5(4) Backflow prevention assemblies for containment.
	a. 	Backflow prevention assemblies for containment shall be installed immediately following the water meter or as close to that location as deemed practical by the administrative authority.
	b. 	A water service determined to present a high hazard shall be protected by an air gap or an approved reduced-pressure principle backflow prevention assembly.
	c. 	A water service determined to present a low hazard shall be protected by an approved double check valve assembly or as in 25.5(4)“b.”
	d. 	A water service to a fire protection system shall be protected from backflow in accordance with the recommendations of American Water Works Association Manual M14. Where backflow prevention is required for a fire protection system, an approved backflow prevention assembly for containment in a fire protection system shall be used.
	25.5(5) Backflow incidents.
	a. 	The customer shall immediately notify the agency providing water service when the customer becomes aware that backflow has occurred in the building, property or private water system receiving water service.
	b. 	The administrative authority may order that a water service be temporarily shut off when a backflow occurs in a customer’s building, property or private water system.
[ARC 8860B, IAB 6/16/10, effective 7/21/10; ARC 1089C, IAB 10/16/13, effective 11/20/13; ARC 2614C, IAB 7/6/16, effective 6/15/16]
These rules are intended to implement Iowa Code chapter 105 as amended by 2013 Iowa Acts, Senate File 427.
[Filed 12/3/81, Notice 9/2/81—published 12/23/81, effective 1/27/82]
[Filed 2/24/84, Notice 10/26/83—published 3/14/84, effective 4/18/84]
[Filed emergency 7/11/86 after Notice 4/23/86—published 7/30/86, effective 7/11/86]
[Filed emergency 7/10/87—published 7/29/87, effective 7/10/87]
[Filed 1/17/89, Notice 11/16/88—published 2/8/89, effective 3/15/89]
[Filed 7/17/92, Notice 1/22/92—published 8/5/92, effective 9/9/92]
[Filed 5/13/96, Notice 3/13/96—published 6/5/96, effective 7/10/96]
[Filed 9/14/01, Notice 8/8/01—published 10/3/01, effective 11/19/01]
[Filed ARC 8860B (Notice ARC 8703B, IAB 4/21/10), IAB 6/16/10, effective 7/21/10]
[Filed ARC 1089C (Notice ARC 0811C, IAB 6/26/13), IAB 10/16/13, effective 11/20/13]
[Filed ARC 2474C (Notice ARC 2317C, IAB 12/23/15), IAB 3/30/16, effective 6/1/16]
[Filed Emergency ARC 2614C, IAB 7/6/16, effective 6/15/16]
[Filed ARC 3062C (Notice ARC 2900C, IAB 1/18/17), IAB 5/10/17, effective 6/14/17]