Stormwater Pollution & Impaired Waters

Every time it rains, some of the water runs off of the land. This is known as stormwater runoff. As stormwater runoff flows across lawns, driveways, streets and parking lots, it picks up pollutants and debris, including sediment (dirt), fertilizer, pesticides, motor oil, grease, heavy metals, toxic chemicals, leaves and grass clippings, pet waste and litter. In addition, pollutants such as sewage, chemicals and chlorinated pool water can directly enter the stormwater system through illicit discharge and illegal connections.

All of these contaminants are carried by stormwater to the nearest stream, river, or lake. A common misconception is that water that runs off streets and parking lots into a storm drain goes to a wastewater treatment plant. In fact, stormwater usually receives no treatment.

Stormwater pollution can make monitoring and treatment of our drinking water more difficult and costly, especially in metro Atlanta where 98% of our drinking water comes from surface water supplies. In addition, it can hinder the health of the aquatic ecosystem and result in the loss of our streams, rivers, and lakes for recreational purposes.

Polluted stormwater runoff is the leading source of water quality degradation and source of impaired waters in the District.  A water is listed as impaired when it fails to meet general federal water quality standards, or the specific standards for its designated use determined by the state.

The Clean Water Act 303(d) list helps the state and federal agencies keep track of what waters are impaired and by what pollutant. The U.S. EPA requires that total maximum daily loads (TMDLs) be determined for waterbodies where water quality standards have not been met.

The District is helping to address stormwater pollution and impaired waters through the watershed management strategies included in District-wide Watershed Management Plan as well as the public awareness and education efforts of the Clean Water Campaign. The District also is facilitating a comprehensive water quality monitoring effort to evaluate progress in meeting water quality goals.