The District of Columbia is committed to improving the quality of its urban waterways. Under a Municipal Separate Storm Sewer System (MS4) permit, the District is obligated to manage and reduce pollution in urban stormwater. In highly urbanized areas, rainfall is unable to drain naturally, instead running off paved surfaces and rooftops, picking up and carrying pollutants (such as toxic chemicals, bacteria, dirt, and trash) to rivers and streams.

The District Department of the Environment (DDOE) is the agency designated with primary responsibility to administer and oversee the District’s MS4 permit.  A major component of the  MS4 permit is the development of a Consolidated Total Maximum Daily Load (TMDL) Implementation Plan which will guide the agency in reducing pollution from the District’s MS4, supporting achievement Clean Water Act goals for District waterways .