Massive Sewage Spill Contaminates Potomac River

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A major sewage spill occurred just outside of Washington, D.C. in January, resulting in over 240 million gallons of untreated waste flowing into the Potomac River. The incident is considered one of the largest sewage spills in the nation's history, raising concerns about environmental damage and public health risks.

Why it matters

The Potomac River is a vital waterway that provides drinking water for millions of people in the region. A spill of this magnitude can have devastating impacts on the local ecosystem, contaminating the water supply and posing serious health hazards for nearby communities.

The details

The sewage spill occurred at a wastewater treatment plant in Prince George's County, Maryland, just outside of Washington, D.C. A mechanical failure at the plant caused the release of over 240 million gallons of untreated sewage into the Potomac River over the course of several days in January.

• The sewage spill began in early January 2026.
• The spill continued for several days before being contained.

What’s next

Authorities are investigating the cause of the mechanical failure at the wastewater treatment plant and are working to assess the full extent of the environmental damage and public health risks.