The District of Columbia beat the federal deadline for updating its stormwater regulations by a weekend when it finalized the new standards today. The management plan includes a first-of-its-kind Stormwater Retention Credit (SRC) trading program, which allows those who voluntarily implement stormwater reductions to sell their credits to other properties or developments in need of off-site solutions.

Stormwater runoff — as you may have noticed during last week’s deluges in the region — can carry oil, pollutants, pet waste and trash into waterways and erode their stream banks. Several municipalities in the Chesapeake Bay watershed have recently updated their stormwater retention requirements or are in the process of doing so. Rooftops, parking lots and other impervious surfaces make up 43 percent of the land area in the District, turning stormwater runoff into a gushing problem at times.

“This new regulatory framework will transform the District’s impervious areas into a more river-friendly landscape,” Keith A. Anderson, director of the District Department of Environment, said in a press release. “It is a critical step toward making District waterbodies more usable and attractive for residents, businesses, and visitors.”

Anderson said the measures will also help the city meet Mayor Vincent Gray’s goal of making all District waterbodies fishable and swimmable by 2032.

Under the new rules, large construction sites or substantial improvement projects that disturb 5,000 square feet or more of land will be required to retain a certain amount of stormwater using rain gardens, permeable pavement, green roofs and other green infrastructure practices. The trading program allows these sites to retain up to half of their stormwater volume offsite, using privately tradable credits or paying a fee to the DDOE, which says the credits will be a more cost-effective option in some cases.

You can read more about the final regulations on the DDOE’s website here: