Combined Sewer Overflows

Combined sewer overflows (CSOs) are a major source of pollution to the Anacostia River with an estimated average 2 billion gallons of untreated sewage mixed with stormwater flows into the Anacostia River each year. These CSOs dump large amounts of bacteria and other pathogens into the water, making it unsafe for swimming and fishing. CSOs also dump trash and other pollutants into the water.

During dry weather, waste flows safely through the District’s combined sewer system to the Blue Plains wastewater treatment plant. Dams within the pipes prevent sewage from flowing to stormwater outfalls along the Anacostia River.

When a big storm occurs, the large volume of stormwater mixed with untreated sewage flows over the in-pipe dams to the outfalls along the river. If this sewage water were blocked from reaching those outfalls, it would back up in the system and could overflow into houses and businesses through toilets and other wastewater drains.

Approximately one third of the District’s area is still served by a combined sewer system. 


Long Term Control Plan for CSOs

As a result of a lawsuit filed against DC Water, it has agreed to implement a $1.9 billion long-term control plan over the next 20 years that would stop 98% of the 3.2 billion gallons of raw sewage mixed with stormwater that dumps into the Anacostia and Potomac Rivers and Rock Creek in the average year.  The Anacostia portion of this plan is to be implemented as a top priority, to be completed in 13 years.

Making sure that this plan actually gets implemented must be a top priority for residents, visitors to the nation’s capital, and all those who would see the health of this once beautiful and vibrant river restored. 30% of the total acreage of the DC portion of the Anacostia watershed is federally owned. Urge your Congressional representatives to provide resources for the clean-up of the CSO problem on the Anacostia River.


Anacostia Riverkeeper advocates for the Long Term Control Plan to reduce combined sewer overflow events and supports the greening of the District in order to control polluted runoff on land before it finds its way into the sewer system.


In The News

"Delay in Pipeline to control Combined Sewer Overflow?"  (12/12/2012)