Senate File 455 - Reprinted SENATE FILE 455 BY COMMITTEE ON LOCAL GOVERNMENT (SUCCESSOR TO SF 34) (As Amended and Passed by the Senate March 15, 2023 ) A BILL FOR An Act relating to the regulation of topsoil and storm water at 1 construction sites. 2 BE IT ENACTED BY THE GENERAL ASSEMBLY OF THE STATE OF IOWA: 3 SF 455 (3) 90 js/ns/mb

S.F. 455 Section 1. Section 331.301, Code 2023, is amended by adding 1 the following new subsection: 2 NEW SUBSECTION . 22. a. For purposes of this subsection: 3 (1) “Construction site” means a site or common plan of 4 residential or commercial development or sale, including the 5 development of a single-unit or multiple-unit residential 6 building. 7 (2) “Topsoil” means the same as defined in section 208.2 and 8 includes amendments to topsoil. 9 b. A county shall not adopt or enforce an ordinance, 10 motion, resolution, or amendment relating to the preservation, 11 compaction, placement, or depth of topsoil at a construction 12 site that is more restrictive than those requirements provided 13 in the national pollutant discharge elimination system general 14 permit no. 2 as issued by the department of natural resources. 15 c. (1) A county may adopt or enforce an ordinance, motion, 16 resolution, or amendment that regulates storm water runoff at a 17 construction site only to the extent that such regulation for 18 rainfall events having a return frequency ranging from five 19 through one hundred years does not require a post-construction 20 storm water flow rate that is more restrictive than the 21 existing flow rate of a rainfall event having a return 22 frequency of five years, with all such runoff rates based on 23 the actual existing condition of the site at the time the 24 construction commences. 25 (2) A county may adopt or enforce an ordinance, motion, 26 resolution, or amendment that regulates storm water runoff 27 from upstream properties adjacent to a construction site to 28 the extent that storm water runoff shall be allowed to pass 29 through downstream storm water basins at the same flow rates as 30 off-site storm water runoff entering the construction site. 31 Sec. 2. Section 364.3, Code 2023, is amended by adding the 32 following new subsection: 33 NEW SUBSECTION . 18. a. For purposes of this subsection: 34 (1) “Construction site” means a site or common plan of 35 -1- SF 455 (3) 90 js/ns/mb 1/ 2

S.F. 455 residential or commercial development or sale, including the 1 development of a single-unit or multiple-unit residential 2 building. 3 (2) “Topsoil” means the same as defined in section 208.2 and 4 includes amendments to topsoil. 5 b. A city shall not adopt or enforce an ordinance, motion, 6 resolution, or amendment relating to the preservation, 7 compaction, placement, or depth of topsoil at a construction 8 site that is more restrictive than those requirements provided 9 in the national pollutant discharge elimination system general 10 permit no. 2 as issued by the department of natural resources. 11 c. (1) A city may adopt or enforce an ordinance, motion, 12 resolution, or amendment that regulates storm water runoff at a 13 construction site only to the extent that such regulation for 14 rainfall events having a return frequency ranging from five 15 through one hundred years does not require a post-construction 16 storm water flow rate that is more restrictive than the 17 existing flow rate of a rainfall event having a return 18 frequency of five years, with all such runoff rates based on 19 the actual existing condition of the site at the time the 20 construction commences. 21 (2) A city may adopt or enforce an ordinance, motion, 22 resolution, or amendment that regulates storm water runoff from 23 upstream properties adjacent to a construction site only to the 24 extent that storm water runoff shall be allowed to pass through 25 downstream storm water basins at the same flow rate as off-site 26 storm water runoff entering the construction site. 27 -2- SF 455 (3) 90 js/ns/mb 2/ 2