Massive Sewage Spill Pollutes Potomac River with Dangerous E. coli Levels

Broken pipe dumps nearly 300 million gallons of contaminated water into river near Washington, D.C.

Jan. 27, 2026 at 2:07pm

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A sewage spill into the Potomac River near Washington, D.C. has polluted the waterway with dangerously high levels of E. coli bacteria, nearly 12,000 times the safe limit for human contact. The spill, caused by a broken 72-inch interceptor pipe, has dumped close to 300 million gallons of contaminated water into the river since it was discovered last week.

Why it matters

The Potomac River is a major source of drinking water and recreation for the Washington, D.C. metropolitan area, so this massive sewage spill poses a serious public health threat. The high levels of E. coli bacteria can cause severe gastrointestinal illness, and the long-term environmental impact on the river ecosystem is still unknown.

The details

The sewage spill occurred in Montgomery County, Maryland, along the Clara Barton Parkway near the Chesapeake and Ohio Canal National Historic Park. Testing by the Potomac Riverkeeper Network found E. coli levels in the river were 11,900 times higher than the safe limit for human contact. Authorities say the spill was caused by a broken 72-inch interceptor pipe that funneled the sewage directly into the Potomac.

  • The broken pipe was discovered last week.
  • The spill has been ongoing since the pipe broke, dumping nearly 300 million gallons of contaminated water into the river.

The players

Potomac Riverkeeper Network

A nonprofit organization dedicated to protecting the Potomac River watershed.

Betsy Nicholas

President of the Potomac Riverkeeper Network.

Dean Naujoks

Potomac Riverkeeper and member of the Potomac Riverkeeper Network.

D.C. Water

The water utility responsible for managing the sewage infrastructure in the Washington, D.C. area.

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What they’re saying

“These measurements of E. coli bacteria show contamination which is nearly 12,000 times what authorities limit for human contact.”

— Betsy Nicholas, President, Potomac Riverkeeper Network

“We sampled the sewage discharging from the broken interceptor pipe to the Potomac River near Lock 10 and the result was 4,884,000 MPN – Most Probable Number for E. coli – which is 11,900 times higher than the 410 MPN limit for safe human contact.”

— Dean Naujoks, Potomac Riverkeeper

“D.C. Water needs to come up with a better plan than using a 100-year-old dry canal ditch to capture and contain future sewage releases instead of discharging hundreds of millions of gallons of sewage to the river. One of the largest sewage spills in U.S. history could have been avoided.”

— Dean Naujoks, Potomac Riverkeeper

What’s next

Authorities are working to contain the spill and assess the full environmental impact. The Potomac Riverkeeper Network is calling on D.C. Water to develop a better plan to prevent future sewage spills of this magnitude.

The takeaway

This massive sewage spill highlights the critical need to invest in aging water infrastructure across the country. The high levels of E. coli contamination pose serious public health risks and could have long-lasting effects on the Potomac River ecosystem. This incident underscores the importance of proactive maintenance and upgrades to prevent such environmental disasters.