DC Water crews and contractors are actively working to construct a bypass system to help control a sanitary sewer overflow coming from the Potomac Interceptor (PI). A section of the 54-mile sewer line collapsed along Clara Barton Parkway, in Montgomery County late Monday, resulting in a significant overflow into the C & O Canal National Historical Park.

Construction of the bypass is critical to containing the overflow and will allow crews to examine the 72-inch diameter sewer pipe and assess the damage. The planned bypass will divert wastewater from upstream of the break by routing it through the currently dry C & O Canal, which will serve as a temporary channel. This bypass is intended to redirect flow back into the Potomac Interceptor downstream of the break, aiming to prevent further overflow into the Potomac River and protect the surrounding environment. 

The PI carries about 60 million gallons of wastewater daily from areas near Dulles Airport, Loudoun and Fairfax Counties, Town of Vienna, Herndon, and Montgomery County, MD to the Blue Plains Advanced Wastewater Treatment Plant for treatment.

Efforts are ongoing to bring the bypass into operation as soon as possible, with teams on-site managing the situation. Once this occurs and the overflow is contained, DC Water and its partners will safely excavate the area to investigate the extent of the damage and determine a timeline for repairs. 

It’s important to note, DC Water's drinking water system is separate from the wastewater system, and we want to reassure the public the drinking water is safe, and water service is NOT affected by this incident. The overflow is downstream from the Washington Aqueduct’s (Aqueduct) intakes at Great Falls. In coordination with the Aqueduct, the intakes are also closed at Little Falls downstream. 

Due to the location of the damaged pipe, close to the Clara Barton Parkway, just east of the 495 interchange, the right inbound lane is closed to traffic. Drivers should anticipate inbound delays toward DC during the morning rush hour and consider alternate routes. 

The C & O Canal Towpath remains open to the public, and there is no breach onto the towpath. We continue working with the National Park Service to monitor the surrounding areas for any signs of impact in the event further action is needed. Residents who live near the impacted area may also notice an odor from the overflow.

The public is advised to avoid any contact with wastewater in this area. Untreated sewage can contain many pathogens causing a variety of illnesses ranging from E. coli to hepatitis. Contact with untreated overflow may cause people to get sick and could bring these pathogens into homes. If you believe you have come into contact with the overflow:

• Leave the area immediately.
• Wash exposed skin thoroughly with soap and clean water.
• Disinfect any affected areas or items.
• Do not consume food or water that may have been exposed.
• Seek medical attention if symptoms occur.
• Report exposure to DC Water at (202) 612-3400.

DC Water is working closely with federal, state and local partners, including the U.S. Environmental Protection Agency (EPA), National Park Service, U.S. Coast Guard, Washington Aqueduct, District Department of Energy and Environment (DOEE), DC HSEMA, Maryland Department of the Environment, and the Montgomery County, Fairfax County and Loudoun County governments. Together, we are coordinating efforts to contain the overflow, monitor environmental impacts, and communicate with the public.

If you have additional questions or need information, you may contact DC Water’s Customer Care team at (202) 354-3600 (Monday-Friday, 8 a.m. to 5 p.m.) or the 24-Hour Command Center at 202-612-3400.