When 240 million gallons of raw sewage spilled into the Potomac River in Washington, D.C., starting in mid-January 2026 and running though mid-March, it was estimated to be the largest sewage spill in U.S. history. But it wasn’t the first, nor will it be the last.

In fact, around the nation, sewage spills are contaminating waterways and communities with unsettling frequency. Sewer systems are designed to be invisible. If toilets flush, most people forget they exist. This invisibility has contributed to chronic underinvestment. Pipes, pump stations and treatment facilities around the country were built in the mid-20th century and are now at or beyond their designed lifespan.

Between December 2019 and February 2020, a series of sewer main breaks in the city of Fort Lauderdale, Florida, led to the release of approximately 219 million gallons of raw sewage into environmentally sensitive waterways. In 2021, the Los Angeles Hyperion Water Reclamation Facility spilled 12.5 million gallons of untreated wastewater into Santa Monica Bay. These events were the results of various aspects of underinvestment, including deferred maintenance and upkeep, delayed replacement and capacities too low for current needs.

The D.C. spill dumped the equivalent of three days’ worth of sewage from 800,000 average U.S. homes, enough to fill 360 Olympic-size swimming pools with raw waste.

As an environmental planning scholar and former senior adviser for the White House Council on Environmental Quality during the implementation of the Bipartisan Infrastructure Law of 2021, I have seen how serious these events can be. But any tallying of sewage spills must also include floods, disasters and heavy rainfalls that have caused backups and overflows of various sizes in cities across the country.

What causes sewer........

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