The Government of the District of Columbia charges the Stormwater Fee to support the implementation of the District’s Municipal Separate Storm Sewer System (MS4) permit. DOEE uses these funds to keep trash and other pollutants out of the rivers, install green infrastructure throughout the District, ensure that new construction and redevelopment projects incorporate green infrastructure, and provide incentives for voluntary retrofits. DC Water collects the IAC to fund its Clean Rivers Project to reduce combined sewer overflows. Both of these fees are billed by DC Water.
The fees are based on the total area of impervious surface—including roofs, driveways, and patios—on a property. Impervious surfaces prevent rainwater from soaking into the ground. The resulting stormwater runoff washes trash, oil, pet waste, and other pollutants into the District’s waterbodies. The sheer volume of this runoff erodes sediment from stream channels, which is deposited in these waterbodies, degrading aquatic habitat. In the Combined Sewer System (CSS), this stormwater volume contributes to overflows of raw sewage mixed with stormwater into District waterbodies.
The DOEE Stormwater Fee and the DC Water Clean Rivers IAC are both calculated using Equivalent Residential Units (ERUs). One ERU is equal to 1,000 square feet of impervious surface. Currently, the Stormwater Fee is $2.67 per ERU. Visit DC Water’s Impervious Area Charge information page for the most current IAC rate. Both fees are charged monthly. DC Water determines the number of ERUs each property is billed through geographic information systems (GIS) analysis and by using photographic flyover data.