A 1960s-era sewer pipe collapse in Washington DC dumped 244 million gallons of raw sewage into the Potomac River in January 2026

On January 19, 2026, a 72-inch diameter section of the Potomac Interceptor — a 54-mile sewer trunk line built in the 1960s — collapsed beneath Clara Barton Parkway in Montgomery County, Maryland. Over the following three weeks, more than 244 million gallons of raw, untreated wastewater poured into the Potomac River and the C&O Canal National Historical Park, making it one of the largest sewage spills in U.S. history. Large boulders had nearly completely blocked the pipe, and investigators believe the blockage traces back to the original 1960s construction, when builders placed large rocks too close to the pipe, allowing them to eventually fall in. E. coli levels in the Potomac spiked to hundreds of times the EPA's safe limit. While drinking water intakes were upstream of the spill, the contamination closed recreational access to miles of the river during a period when communities rely on it. The political fallout was immediate — Virginia, Maryland, and DC officials clashed over responsibility and cost-sharing for a pipe that crosses jurisdictional boundaries. DC Water, which operates the interceptor, scrambled to build a bypass using the C&O Canal itself to reroute wastewater, containing the overflow within 21 days. But subsequent inspections revealed two more sections of the Potomac Interceptor rated at high risk of similar failure. This incident exposes a systemic problem: America's major sewer trunk lines were built 50-70 years ago, and most have never been comprehensively inspected using modern technology because they are too large, too deep, and carry too much flow to easily take offline. The Potomac Interceptor serves the entire DC metropolitan area's wastewater needs, making it a single point of failure with no redundancy. The pipe's failure mode — construction defects from the 1960s only now manifesting — illustrates how aging infrastructure can harbor invisible time bombs. There is no national inventory of trunk sewer condition, and utilities rarely have the budget or political will to proactively replace lines that appear to be functioning. The EPA estimates $630 billion in wastewater infrastructure needs over the next 20 years, but the U.S. water utility sector faced an estimated $110 billion funding gap in 2024 alone.