Cleaning efforts continue today on the Potomac Interceptor, to remove debris and obstructions inside the damaged section of the sewer line. The 72-inch pipe collapsed two weeks ago along Clara Barton Parkway and the 495 interchange and the C & O Canal National Historical Park in Montgomery County, Md.  Here is an update on the ongoing work. 

Potomac Interceptor Overflow Update
Monday, February 2, 2026

Containment

• The vast majority of flows have been contained.
• Site containment is capturing residual wastewater from excavation and cleaning, as well as a brief release of wastewater due to a pumping issue.
• Eight bypass pumps are available to provide plenty of capacity for cleaning and maintenance.
• Extra shoring was installed at the collapse site to stop erosion and keep things contained.

Excavation and Cleaning

• Vacuum trucks are clearing pipe blockages, moving carefully toward the damaged section to avoid sending debris downstream.
• We estimate several hundred tons of debris inside the pipe, though the exact amount is still unclear.
• So far, we've cleared nine tons of debris from the pipe.
• Debris includes sections of the damaged pipeline’s interior walls.
• Cleaning is expected to take multiple days based on the type of debris found and potential for additional debris filling the pipe from the collapse site.
• A second access point to the sewer pipe for cleaning has been opened downstream.
• Large rocks and boulders too big for the vacuum are being removed manually from the interceptor slowing the cleaning process.
• Debris includes sections of the damaged pipeline’s interior walls.
• Crews and equipment are prepared and ready for potential snow overnight.
• Heat tents and heating equipment are in place to help mitigate equipment and operational challenges posed by the extreme cold and possible snow.

Environmental Impacts and Evaluation

• DC Water has hired independent experts to sample water and assess the environmental impact and remediation measures.
• Early water quality sampling indicates decreasing bacteria levels at the drainage channel by Lock 10 where the sewer overflow had entered the Potomac River, as well as at Fletcher’s Boathouse.
• More water sampling will be needed to establish a statistical sample size to draw conclusions and establish a trend.
• We are working to develop cleanup and remediation plans, which remain in the early stages and will be focused on immediately impacted areas such as the canal, drainage channels and portions of the Potomac River.
• Cleanup measures will be determined in conjunction with federal, state, and local regulatory agencies.

Timeline for Repair

• A timeline for repair has not been determined.
• Once cleaning of the failure area is complete, we will assess the damage and determine a plan and timeline for repair.