Sewer line collapse triggers wastewater spill into C&O Canal near Clara Barton Parkway

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Sewer line collapse triggers wastewater spill into C&O Canal near Clara Barton Parkway

Will Vitka | [e-mail]
January 21, 2026, 6:23 AM


DC Water crews and contractors are actively working to construct a bypass system to help control a sanitary sewer overflow coming from the Potomac Interceptor.(Courtesy DC Water)

D.C. Water crews are racing to build an emergency bypass system after a major section of a sewer line collapsed late Monday along Clara Barton Parkway in Montgomery County, triggering a significant sanitary sewer overflow into the C&O Canal National Historical Park.

The collapse involves a 72-inch section of the Potomac Interceptor, a 54-mile sewer line that carries roughly 60 million gallons of wastewater a day from communities near Dulles International Airport, Loudoun and Fairfax counties, the towns of Vienna and Herndon, and parts of Montgomery County, to the Blue Plains Advanced Wastewater Treatment Plant for treatment.

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To contain the overflow, D.C. Water is constructing a temporary bypass designed to divert wastewater upstream of the collapse. ... The plan says flow will be routed through a dry stretch of the C&O Canal — a temporary channel, then go back into the Potomac Interceptor downstream of the damaged section. Officials say the bypass is critical to stopping additional overflow and protecting the Potomac River and surrounding environment.

Once the bypass is operational and flows are under control, crews will excavate the damaged area to assess the extent of the collapse and determine how long permanent repairs will take.

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Will Vitka
William Vitka is a Digital Writer/Editor for WTOP.com. He's been in the news industry for over a decade. Before joining WTOP, he worked for CBS News, Stuff Magazine, The New York Post and wrote a variety of books—about a dozen of them, with more to come.
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