Washington’s Sewage Apocalypse
March 18, 2026
On January 19, a six-foot-wide sewer pipe broke beneath the land alongside the Potomac River, nine miles northwest of the Lincoln Memorial. A landslide of dirt and rocks dammed the flow, and the products of a million toilets, showers, sinks, and washing machines in the Washington, D.C., suburbs shot up to the surface and gushed into the watershed. According to researchers at the University of Maryland, it was one of the worst raw-sewage spills in U.S. history.
Two months later, there is no official explanation of what went wrong, and the gist of the DC Water report released on March 5 is, roughly, We did everything right. “This was an unprecedented event,” the CEO, David Gadis, said in a press release. “After evaluating our inspection reports and ratings we do not believe there was any reason to change the timing for our planned rehabilitation, which was to start this summer.”
But something did go wrong. In addition to the damage to the watershed, where the utility has elsewhere spent billions of dollars to keep out sewage, Maryland’s C&O Canal spent nearly two months functioning as a jury-rigged open-air sewer to bypass the collapse and has been coated in human muck several inches deep. If the collapse had occurred a few miles upstream, it would have contaminated the intake of the Washington Aqueduct, cutting off the water supply for about 1 million people.
Two investigations into the cause of the collapse are ongoing. But DC Water officials have begun to hint at a possible culprit: a design flaw that has been lurking above the underground pipe since it was installed in the early 1960s, in the form of large boulders that were used as fill when the pipe was buried. This weakness raises the possibility of other land mines along the pipeline’s 54-mile path. The utility is now turning to archival drawings to identify spots with similar methods of construction, and contemplating drilling to assess the risk. Everyone who was involved in designing the interstate sewer is long gone.