Senate File 455 - Introduced SENATE FILE 455 BY COMMITTEE ON LOCAL GOVERNMENT (SUCCESSOR TO SF 34) 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 TLSB 1480SV (2) 90 js/ns

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. 13 c. (1) A county may adopt or enforce an ordinance, motion, 14 resolution, or amendment that regulates storm water runoff at a 15 construction site only to the extent that such regulation does 16 not require a post-construction storm water flow rate that is 17 more restrictive than the existing flow rate of the same storm 18 event, with all such runoff rates based on the actual existing 19 condition of the site at the time the construction commences. 20 (2) A county may adopt or enforce an ordinance, motion, 21 resolution, or amendment that regulates storm water runoff 22 from upstream properties adjacent to a construction site to 23 the extent that storm water runoff shall be allowed to pass 24 through downstream storm water basins at the same flow rates as 25 off-site storm water runoff entering the construction site. 26 Sec. 2. Section 364.3, Code 2023, is amended by adding the 27 following new subsection: 28 NEW SUBSECTION . 18. a. For purposes of this subsection: 29 (1) “Construction site” means a site or common plan of 30 residential or commercial development or sale, including the 31 development of a single-unit or multiple-unit residential 32 building. 33 (2) “Topsoil” means the same as defined in section 208.2 and 34 includes amendments to topsoil. 35 -1- LSB 1480SV (2) 90 js/ns 1/ 3

S.F. 455 b. A city shall not adopt or enforce an ordinance, motion, 1 resolution, or amendment relating to the preservation, 2 compaction, placement, or depth of topsoil at a construction 3 site. 4 c. (1) A city may adopt or enforce an ordinance, motion, 5 resolution, or amendment that regulates storm water runoff at a 6 construction site only to the extent that such regulation does 7 not require a post-construction storm water flow rate that is 8 more restrictive than the existing flow rate of the same storm 9 event, with all such runoff rates based on the actual existing 10 condition of the site at the time the construction commences. 11 (2) A city may adopt or enforce an ordinance, motion, 12 resolution, or amendment that regulates storm water runoff from 13 upstream properties adjacent to a construction site only to the 14 extent that storm water runoff shall be allowed to pass through 15 downstream storm water basins at the same flow rate as off-site 16 storm water runoff entering the construction site. 17 EXPLANATION 18 The inclusion of this explanation does not constitute agreement with 19 the explanation’s substance by the members of the general assembly. 20 This bill relates to the regulation of topsoil and storm 21 water at construction sites. The bill prohibits a county 22 or city from adopting or enforcing an ordinance, motion, 23 resolution, or amendment relating to the preservation, 24 compaction, placement, or depth of topsoil at a construction 25 site. The bill authorizes a county or city to adopt or enforce 26 an ordinance, motion, resolution, or amendment that regulates 27 storm water runoff at a construction site only to the extent 28 that such regulation does not require a post-construction storm 29 water flow rate that is more restrictive than the existing flow 30 rate of the same storm event, with all such runoff rates based 31 on the actual existing condition of the site at the time the 32 construction commences. Additionally, a county or city may 33 adopt or enforce an ordinance, motion, resolution, or amendment 34 that regulates storm water runoff from upstream properties 35 -2- LSB 1480SV (2) 90 js/ns 2/ 3

S.F. 455 adjacent to a construction site only to the extent that storm 1 water runoff shall be allowed to pass through downstream storm 2 water basins at the same flow rate as off-site storm water 3 runoff entering the construction site. 4 -3- LSB 1480SV (2) 90 js/ns 3/ 3