Massive Sewage Spill Contaminates Potomac River

High E. coli levels found extending from Montgomery County into Washington, D.C.

Jan. 27, 2026 at 8:47pm

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A week after a massive underground sewer line broke in the Potomac River, an estimated 300 million gallons of sewage spilled into the waterway. Testing revealed dangerously high E. coli levels extending from Montgomery County into Washington, D.C., raising concerns about public health and the river's ecosystem.

Why it matters

The Potomac River is a vital natural resource for the region, providing drinking water, recreational opportunities, and supporting diverse wildlife. A sewage spill of this magnitude poses serious risks to public health and the local environment, underscoring the need for robust infrastructure and emergency response plans to prevent such incidents.

The details

Over the weekend, DC Water crews diverted most of the sewage into the empty C&O Canal to minimize the impact on the river. However, the stream pushing millions of gallons of sewage into the river each day has not been fully repaired. Potomac Riverkeepers found alarmingly high levels of sewage E. coli in the river, both near the discharge site and several miles downstream.

  • The sewer line broke on January 19, 2026.
  • The sewage spill has been ongoing for over a week.

The players

Potomac Riverkeepers

A nonprofit organization dedicated to protecting the Potomac River and its tributaries.

DC Water

The water and sewer utility serving the District of Columbia.

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What they’re saying

“I'm glad that DC Water's come up with a plan to try and divert the flow and minimize the impacts of the river. But again, is this going to continue to work, and how long will it take to actually fix this problem before no sewage is discharging to the Potomac River, and then they still have to clean this mess up?”

— Dean Naujoks, Potomac Riverkeepers

“We found alarmingly high numbers of sewage E. coli in the river. We also tested in the river right below the discharge. Then we tested all the way down, about four miles down. And everywhere we tested downstream, we found very, very high levels of E. coli.”

— Dean Naujoks, Potomac Riverkeepers

What’s next

DC Water has not provided an estimate for how long the containment or final cleanup will take, raising concerns about the long-term impact on the Potomac River's water quality and ecosystem.

The takeaway

This incident underscores the critical importance of maintaining and upgrading aging water infrastructure to prevent such large-scale sewage spills, which can have devastating consequences for public health and the environment. It also highlights the need for robust emergency response plans and coordination between local authorities to quickly address and mitigate the impacts of such incidents.