Communities are responsible for maintaining stormwater systems, including pipes, culverts, detention basins, green infrastructure, and flood control features. These systems require ongoing maintenance, repair, and upgrades to function properly and meet state and federal regulations. To cover these costs, many communities have established stormwater utilities and collect a monthly fee from property owners, similar to water or sewer services.
How utility rates are set
Stormwater fees are not based on the value of the home or how much land it sits on; rather, fees are based on the amount of surfaces that create runoff.
Most Iowa cities calculate stormwater fees using a unit called an Equivalent Residential Unit, or ERU. One ERU represents the average amount of impervious surface found on a typical single-family home, such as rooftops and driveways. The specific square footage defined as one ERU varies by city. For example, Johnston uses 4,000 square feet, while Urbandale uses 3,200 square feet.
Each city sets its own monthly fee per ERU. Current rates in Iowa generally range from $3 to $15 per month, depending on local infrastructure needs and funding levels.
Utility rate surveys
ISWEP conducts a biannual survey of the stormwater utility fees managed by member cities. The next survey will be conducted in the summer of 2025.
2024 Western Kentucky University Stormwater Utility Survey
2022 Stormwater Utility Fee Data (Table)
2022 Stormwater Management Program Data (Table)
2022 Stormwater Utility Fee Survey (Key Metrics)
2021 Black & Veatch Stormwater Utility Survey Report
