Community Engagement | Environmental Rehabilitation Plan | Inspection Reports | Media | What Happened
Potomac Interceptor Rehabilitation Project
For information about DC Water's 10-year, $625 million rehabilitation project for the Potomac Interceptor and the latest information about ongoing rehabiltation efforts and emergency repairs go to the Potomac Interceptor Page.
We Want to Hear from You
Got a comment or question? Please click on the button below to share your feedback.
Community Engagement
DC Water and partner agencies in the District, Maryland and Virginia have hosted a series of community meetings to provide updates on the Potomac Interceptor response, and to answer questions from residents and stakeholders.
DC Water has also been providing regular updates and documentation to Congress since the Potomac Interceptor collapse in January.
On May 20, 2026, DC Water Chief Executive Officer and General Manager David L. Gadis testified before the House Energy and Commerce Committee’s Subcommittee on Oversight and Investigations regarding the Potomac Interceptor collapse to update members on our emergency response, ongoing rehabilitation efforts, and what we are doing to prevent future incidents.
His written testimony provided to the committee is available here.
Click on the Engage button below to watch videos of previous meetings or download the presentations.
Environmental Rehabilitation Plan
On February 28, NPS issued a Special Use Permit for the repair, rehabilitation, and environmental restoration of the C&O Canal National Historical Park and surrounding area of the Potomac Interceptor collapse between Locks 10 and 14.
DC Water in coordination with the U.S. Army Corps of Engineers, the U.S. Environmental Protection Agency, and the National Park Service (NPS) has completed the initial clean-up and reseeding in the areas directly impacted by the overflow, along the drainage channel, culvert, and tributary to the Potomac River.
As part of our continued committment to restore the surrounding environment, DC Water has outlined its next steps to complete the environmental cleanup and its plan for continued water quality monitoring this summer. The plan, submitted to the Maryland Department of the Environment (MDE), is supported by extensive data from hundreds of samples that indicate bacteria levels since at least mid-March have been back to normal.
Under the proposal, further confirmation of water quality testing will continue daily through July 5 at the ten existing sampling sites and then transition to weekly testing through September 10. While there is no technical basis to continue the monitoring, DC Water will do so during the remaining summer months to reinforce for the public that river bacteria levels are back to normal.
In addition, the first phase of comprehensive environmental restoration efforts is expected to be substantially completed by late summer 2026. The ongoing work is focused on removing the remaining affected soil in the C & O Canal which was successfully used as a bypass for up to two billion gallons of wastewater during the repair period.
The second phase of restoration is expected to be completed in the fall. This includes a comprehensive plan to replant native herbaceous species, shrubs, and trees, regrading temporarily impacted wetlands, and restoration of natural hydrology. Crews will also repair the C & O Canal’s clay liner, add topsoil for the base and sides, and restore structural features.
The public is encouraged to provide their feedback. Below is the current proposed environmental rehabiltation plan, as well as the initial plan and NPS permit.
- Potomac Interceptor Emergency Repair and Rehabilitation Plan - April 2026
- Environmental Rehabilitation Plan - February 2026
- NPS Special Use Permit
If you would like to share any comments about the Environmental Rehabilitation Plan with the project team, please click on the button below.
Comprehensive Condition Assessment
On Thursday, March 5, DC Water released a comprehensive assessment detailing the condition of the Potomac Interceptor and our emergency response to the January 19 sanitary sewer line failure. This report provides clarity for customers, stakeholders, and community members about the steps taken and findings from the incident, including prior inspections of the pipe’s condition.
Click here to view the report and pipe inspection videos.
We detailed our findings in this Press Release.
Background
- Collapse of 72" diameter section of pipe caused overflow of more than 200 million gallons of wastewater into Potomac River.
- Bypass system rerouted the wastewater around the collapse to limit overflows.
- Emergency repairs are complete and full flow was returned to the Potomac Interceptor on March 14.
- DC Water is testing the river for E. Coli. The sampling results are posted below.
- Drinking water is not impacted.
Media
Bacteria Sampling
Information on water quality sampling and results can now be found at the top of the page.
Drinking Water is not Impacted
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.
What Happened
On January 19, 2026, a section of the 54-mile Potomac Interceptor (PI) sewer line collapsed along Clara Barton Parkway, in Montgomery County, resulting in a significant overflow into the C & O Canal National Historical Park. The PI carries an average of up to 60 million gallons of wastewater daily from as far away as Dulles Airport to the Blue Plains Advanced Wastewater Treatment Plant in Southwest DC for treatment.
Within five days, DC Water crews and contractors constructed a bypass to help contain the overflow. On January 24, utilizing powerful pumps and the C & O Canal, wastewater was rerouted around the collapsed section of pipe and back into the sewer system. The last overflow to reach the Potomac River occured February 8, and within 21 days all overflows were contained.
Additional pumping capacity was brought in, and a bulkhead gate installed to block flow in the pipe to allow for emergency repairs. As work to repair the pipe continued, DC Water also developed its initial Environmental Rehabilitation Plan in conjunction with state and federal regulators. Clean-up efforts in the areas directly impacted by the overflows began on March 2.
Emergency repairs were completed on March 14, and the flow was successfully returned to the Potomac Interceptor. Once this occured, the bypass pumps were turned off allowing the C & O Canal to drain and for work to get underway to clean and rehabilitate the canal.
Construction has now transitioned to the previously planned long-term rehabilitation of more than 2700 linear feet of the Potomac Interceptor in this area. The work is expected to take 9-10 months and will strengthen and reinforce the pipe to like-new condition.
