What’s Up With the Spill?
By • March 10, 2026 0 268
By Leland Schwartz
Using the C&O Canal as a bypass patch for the section of the Potomac Interceptor sewer line that collapsed in mid-January will soon be no longer necessary. Crews are shooting for mid-March to complete the emergency pipe repairs between Locks 10 and 14.
After that, according to DC Water spokesperson Sherri Lewis, long-term rehabilitation efforts will begin, requiring the upgrading of about a mile’s worth of separate sections of pipe.
Repair crews will use “slip lining,” in which a smaller pipe is put inside the original pipe. On others, because of the terrain involved, they will spray the pipes with a geopolymer that hardens like concrete, restoring the structural integrity of the pipes. Upgrading the pipe is expected to take nine to 10 months.
“This kind of collapse is unprecedented and was not what we would typically see when a failure occurs,” Lewis said. “One of the contributing factors to the scale and magnitude of the collapse were the rocks and boulders on top of the pipe that were excavated and used as backfill during the original 1960s construction.”
Millions of gallons of sewage spilled into the Potomac River in mid-January. NBC Washington screenshot.
This exacerbated the incident, she explained, “because the rocks and boulders effectively blocked most flow through the pipe and required a more extensive process to isolate the pipe and safely remove the rock and debris dam inside.”
The House Committee on Energy and Commerce is investigating what caused the incident, saying that “understanding the nature of how this incident occurred and how future incidents of this scale may be prevented in the future is imperative.”
The committee has asked DC Water myriad questions, including whether it has analyzed how the spill will impact tourism.
In its recent letter to DC Water, the committee worried about the spill coming shortly before the National Cherry Blossom Festival and the 250th anniversary of the signing of the Declaration of Independence.
DC Water “continues to evaluate the environmental impacts of the overflow” and is exploring further restoration efforts “based on input from concerned residents and community groups, along with the ongoing collaboration with federal, state and local regulators overseeing the environmental restoration.”
The recreational advisory for the Potomac River has been lifted because “consistent water quality testing shows bacteria levels are within safe ranges for recreation.”
Asked what DC Water needs the most, Lewis said: “We welcome assistance from our various federal, state and local partners to support our repair efforts and the environmental restoration.”
