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

Iowa City Code 16-3G-10 establishes a single stormwater utility district covering the entire city to fund management of storm water runoff quantity and quality, drainage construction, and debt service. Under 16-3G-10(E), an equivalent residential unit (ERU) equals 3,129 square feet of impervious area, and every owner or occupant of non-exempt developed property must pay a monthly stormwater utility charge, with the actual ERU rate set separately in Code 3-4-6. Section 16-3G-10(F) sets the formula: single-family residential property pays 100% of the ERU rate per month; multi-family property pays 50% of the ERU rate multiplied by the number of dwelling units; nonresidential property pays a base rate of one full ERU plus two dollars multiplied by the property's impervious area divided by the ERU size.

Charges begin at the earliest of certificate of occupancy, 90 days after construction halts at least 50% complete, or 90 days after construction finishes. University of Iowa property, public streets, alleys, sidewalks, and undeveloped land are exempt under the ERU definitions in 16-3G-10(B). Nonresidential properties holding an NPDES industrial stormwater permit from the Iowa DNR qualify for a 50% credit on their monthly bill under 16-3G-10(H). Property owners may appeal a unit count, impervious area, or charge calculation to the Director under 16-3G-10(G), with further review available from the City Manager and City Council; filing an appeal does not excuse payment, but excessive charges paid during an appeal are refunded with interest.