DC Water nears containment of Potomac Interceptor overflow as bypass operations continue

DC Water is close to containing a significant sewer overflow caused by a collapse in the Potomac Interceptor, with efforts focused on drainage, repairs, and environmental safety amid winter challenges.

Jan. 27, 2026

2 min read

The C & O Canal, at Chesapeake & Ohio Canal National Historical Park, Maryland

DC Water is nearing full containment of a major sanitary sewer overflow caused by the collapse of a 72-inch section of the Potomac Interceptor along Clara Barton Parkway and the C&O Canal National Historical Park in Montgomery County, Maryland. The failure, which occurred Jan. 19, 2026, sent untreated wastewater into a creek bed leading to the Potomac River and prompted an around-the-clock emergency response.

A temporary bypass system was activated late Jan. 24, allowing wastewater to be diverted around the damaged pipe and back into the interceptor downstream. In the first full day of operation, flow returning to the system increased by approximately 40 million gallons per day, indicating significant progress toward containment. Some overflow remains at the break site due to residual wastewater trapped at a lower elevation, but additional pumps are being installed to accelerate drainage and reach full containment.

Chesapeake and Ohio Canal or the C and O Canal, in the Georgetown neighborhood of Washington, D. C

DC Water advances bypass efforts after Potomac Interceptor collapse

DC Water is deploying temporary measures, including high-capacity pumps and canal bypasses, to contain a sewer overflow caused by the collapse of the Potomac Interceptor near ...

The Potomac Interceptor conveys up to 60 million gallons per day from parts of Maryland and Virginia to DC Water’s Blue Plains Advanced Wastewater Treatment Plant. The bypass uses a contained, 2,700-foot section of the C&O Canal, implemented in coordination with the National Park Service, to safely route wastewater around the collapse.

Winter weather has complicated operations, with heavy snow and freezing temperatures requiring frequent maintenance of pumps clogged by fats, oils, grease, wipes and debris. DC Water has added pumping capacity and redundancy to maintain operations and reduce overflow volumes.

Once containment is achieved, crews will excavate and inspect the damaged pipe, stabilize surrounding soils and develop a long-term repair plan. DC Water will also work with state and federal agencies to assess environmental impacts and remediation needs.

Drinking water remains unaffected, as the incident occurred downstream of drinking water intakes. DC Water continues to remind the public to avoid posted areas and contact with untreated wastewater.