Potomac Interceptor Repairs Update 
March 1, 2026

• Today marks a milestone, as we reach the three-week point with no overflows entering the Potomac River. The last release to reach the river occurred on February 8.
• On February 28, National Park Service (NPS) issued a Special Use Permit for the repair, rehabilitation, and environmental restoration of the Potomac Interceptor and the C&O Canal National Historical Park at the area of the Potomac Interceptor collapse between Locks 10 and 14.
• Work continues to clean the pipe upstream and downstream from the damaged section of the Potomac Interceptor. Teams are also clearing trees, brush, and contaminated debris in and around the collapse site under the supervision of NPS as part of the NPS approved environmental restoration work underway.
• A CCTV inspection on the upstream pipe section was done, and cleaning is expected to be completed tomorrow. This will be followed by pressure washing the upstream section to prepare for the application of the geopolymer lining.
• Cleaning continues downstream of the damaged pipe section and once the emergency repair work is completed upstream, the geopolymer work will move to the downstream section.
• The geopolymer, a material similar in strength to concrete, will reinforce and strengthen the pipe. Geopolymer is sprayed on and must cure between layers until it reaches the desired thickness.
• The start of geopolymer work this week keeps the emergency repair on track to be completed mid-March, when the full flow of wastewater will be restored to the Potomac Interceptor and the bypass pumping system will no longer be necessary.
• Starting tomorrow, DC Water and its contractor will begin hauling the contaminated brush and soil from the site for proper disposal.
• Environmental restoration work will continue but may be impacted by weather conditions and forecasted rain and snow. The clean-up must be done in dry conditions to prevent further contamination.

DC Water remains committed to protecting public health and safety and ensuring the environmental restoration is performed in the immediate areas around the collapse site and areas of the Potomac River in coordination with NPS and MDE.

Water Quality Sampling

DC Water is performing daily water quality sampling. It’s important to note that historically the E. coli levels in the Potomac and Anacostia rivers vary widely from day to day. This is reflected in recent sampling results with stormwater runoff from rain and snow impacting water quality. Fluctuations in water quality are influenced by factors such as weather events, river flow, runoff, pollutants, releases of combined overflows, and other sources discharging into waterways.

Given these variables, measurements taken much further downstream cannot be attributed solely to this incident.

For the Potomac River, historical water quality data shows E. coli levels may vary from a range as low as 10 MPN/100mL to as much as 5,000 MPN/100mL on a given day. A more detailed explanation is posted on the District Department of Energy and Environment (DOEE) website at doee.dc.gov/release/potomac-interceptor-update-and-faqs.

Below are the results of sampling during the period from February 16 – present. Past results may be found on our dedicated Potomac Interceptor Response page.

For the latest on the Potomac Interceptor repair efforts, including news and updates, water quality sampling results, and additional information go to dcwater.com/potomac-interceptor-collapse.