District of Columbia issues Potomac River contact warning after upstream sewer collapse and ongoing overflow risk

Public urged to avoid river contact as untreated sewage impacts waters flowing through Washington

District officials are advising residents and visitors to avoid unnecessary contact with water from the Potomac River after a major sewer line collapse upstream in Maryland sent untreated wastewater into the river system that flows through Washington. The warning covers direct water contact and activities that can increase exposure risk, including fishing and allowing pets into the water.

The incident began on January 19, 2026, when a 72-inch sewer pipe segment on the Potomac Interceptor failed near the Clara Barton Parkway and Interstate 495 area in Montgomery County, adjacent to the Chesapeake & Ohio Canal National Historical Park. The Potomac Interceptor is a major wastewater conveyance line; the break initially released very large volumes of untreated sewage into the river.

What officials say is affected—and what is not

District agencies emphasize that the city’s drinking water remains safe and is not part of the same system as the wastewater line that failed. The advisory is focused on the health risks associated with pathogens commonly present in raw sewage, including E. coli, as well as other bacteria and viruses that can cause gastrointestinal and skin, ear, and respiratory infections.

The public guidance is precautionary: avoid contact with Potomac River water in the District until water-quality conditions are better characterized and sustained sampling shows reduced risk.

Repair work and residual overflow risk

Crews established a bypass system within days of the collapse to divert wastewater around the failure point and back into the interceptor farther downstream. D.C. Water has reported that the bypass has substantially reduced releases, but the system remains vulnerable to operational disruptions and increased flows associated with snowmelt and infiltration. The utility has also described recurring clogs linked to non-dissolvable wipes and grease, which can temporarily reduce pumping capacity and contribute to minor overflows near the site.

In updates issued in early February, the utility said some limited overflows had occurred near the collapse area during maintenance or high-flow conditions, while containment measures were used to prevent wastewater from reaching the river in certain instances. Water-quality sampling has continued at multiple points downstream, with officials describing variability in bacteria levels influenced by weather, runoff, and infrastructure conditions.

Health and safety guidance for the public

• Avoid swimming, wading, or any activity that could lead to ingesting river water.
• Avoid fishing until advisories are lifted and conditions are confirmed safe.
• Keep pets away from the shoreline and any visible discolored water or odor.
• Wash hands and exposed skin after any incidental contact; seek medical advice if symptoms develop after exposure.

Broader implications

The Potomac advisory comes amid renewed attention on the region’s aging wastewater infrastructure and the operational challenges of emergency repairs in winter conditions. Officials in the District, Maryland, and downstream jurisdictions continue monitoring river conditions while repair and restoration planning proceeds, with the duration of full, permanent repairs expected to extend well beyond initial containment measures.