Feb 21, 2026:

Donald Trump approved federal disaster assistance requested by Washington, DC Mayor Muriel Bowser.

Feb 19, 2026:

DC Water announced that they have reached the damaged section of sewage pipe causing the leak:

DC Water has successfully reached the damaged section of the Potomac Interceptor, marking a critical step in the ongoing damage assessment and repair efforts. Crews today are manually digging out the affected area, carefully removing sludge, soil, and debris from the collapsed pipe. The work is slow and painstaking, as large boulders and rocks complicate the excavation process. Crews are using both manual labor and an excavator to clear obstructions, working carefully not to cause any additional damage.

Crews were able to reach the damaged pipe section, after the successful installation of a steel bulkhead gate that is now blocking all flow in the pipe. At the same time, the enhanced bypass pumping system is fully operational and diverting wastewater around the collapse site and back into the Potomac Interceptor further downstream. This critical step has enabled workers to access the site safely and begin assessing the pipe for repairs. The manual nature of this work underscores the complexity of the situation and the debris at the collapse site must be removed to fully expose the pipe for engineers to evaluate the damage inside.

Feb 18, 2026:

Washington, DC Mayor Muriel Bowser requested federal support through a Presidential Emergency Disaster Declaration request.

Feb 11, 2026:

DC Water CEO David L. Gadis posted an open letter regarding the sewage overflow.

Feb 6, 2026:

Employing a "contracted environmental firm and certified laboratory," DC Water initiated daily sampling for E. Coli.

Jan 29, 2026:

DC Water released new findings regarding the environmental impacts of the pipe collapse:

Based on flow monitoring data collected before and after interim bypass pumping was activated, DC Water estimates that approximately 243 million gallons of wastewater has overflowed from the collapse site. The vast majority of this volume, approximately 194 million gallons, occurred within the first five days, prior to the overflows being significantly reduced through bypass pumping operations.

Analysis of Potomac River flow data indicates that the estimated peak discharge of wastewater, approximately 40 million gallons per day, represents about 2% of the Potomac River's total flow during that period.

Ongoing water quality monitoring continues to show improving conditions downstream of the discharge point near Lock 10. Since February 1, E. coli concentrations at all downstream sampling locations have remained within the US Environmental Protection Agency's acceptable range for primary contact recreational activities, apart from a single day at Fletcher's Boathouse.

Jan 24, 2026:

DC Water issued a press release stating that a bypass system has been activated:

This evening, DC Water and its contractors turned on the pumps and activated the bypass to contain the wastewater overflows from the damaged Potomac Interceptor sewer line.

Crews completed the installation of six high-powered pumps on Saturday to reroute wastewater around a collapsed section of the Potomac Interceptor along Clara Barton Parkway in Montgomery County, MD and the C & O Canal National Historic Park.

The pumps are positioned upstream of the collapse, each one having the capability to pump up to seven million gallons of wastewater a day from the sewer line, into an isolated section of the C & O Canal and then rerouted back into the sewer pipe further downstream of the collapse.

The bypass allows for excavation and repairs to begin at the site of the collapse.

Jan 19, 2026:

In a press release, DC Water, formerly known as District of Columbia Water and Sewer Authority (DCWASA), announced an investigation into a Sanitary Sewer Overflow from the Potomac Interceptor sewer line near the Potomac River in Montgomery County, Maryland.

According to the press release:

Flow was observed coming out of the PI [Potomac Interceptor] this evening, and DC Water has mobilized its crews and contractors to mitigate the overflow and keep it contained as much as possible so they can assess the damage and begin repairs.

The overflow is expected to reach the Potomac River. It is important to note that DC Water's drinking water system is separate from the wastewater system and is NOT affected by the overflow.

Residents who live near the impacted area may notice an odor from the overflow. Emergency measures will be taken to prevent further spillage. The extent of the repairs and duration are still being determined.

An 8-month construction project to rehabilitate the section of sewer pipe where the overflow/collapse occurred began on September 9, 2025.