Iowa City, IA Environmental Rules: Stormwater Management (2026)

Iowa City's stormwater program runs on a stack of overlapping authorities. Locally, Title 15 Chapter 3 sets the design and construction standards for the public stormwater system and § 15-3-8 governs stormwater management requirements; Title 16 Chapter 3 Article G covers the engineering of dry- and wet-bottom stormwater management facilities used to meet those requirements (basins, ponds, bioswales). Subdivision review under Title 15 requires every new subdivision and most site plan applications to include drainage and stormwater management calculations sufficient to mitigate peak-runoff increases from the developed condition. At the state level, Iowa's surface-water and water-quality program is in Iowa Code Chapter 455B (Iowa Department of Natural Resources - Water Quality), which delegates federal Clean Water Act NPDES authority to Iowa DNR. Iowa Admin. Code 567 Chapter 60 contains the Iowa NPDES rules and Chapter 64 contains the construction-site and MS4 permits. As an MS4 community, Iowa City holds a general NPDES MS4 permit and must implement the Six Minimum Control Measures: public education and outreach, public involvement, illicit-discharge detection and elimination, construction-site runoff control, post-construction stormwater management, and pollution prevention / good housekeeping. Iowa DNR's NPDES General Permit No. 2 (construction sites) is triggered by earth disturbance of one acre or more (or smaller sites that are part of a larger common plan of development). Federally, the underlying authority is the Clean Water Act § 402 (33 U.S.C. § 1342). Iowa City's principal receiving waters are the Iowa River and Ralston Creek; chlorinated pool water, sediment, paint, washwater, and other non-stormwater discharges to the storm sewer are illicit discharges prohibited by the MS4 permit. The City Engineering Division at City Hall (410 East Washington Street) reviews stormwater submittals and inspects construction sites under the local ordinance and the state Construction Site NPDES permit.