Maryland Attorney General Anthony G. Brown and the Maryland Department of the Environment filed a civil lawsuit Monday against the District of Columbia Water and Sewer Authority, known as DC Water, seeking penalties and damages for environmental harm from a major sewage spill into the Potomac River. The complaint, filed in Montgomery County Circuit Court, alleges the utility knew of corrosion in an aging sewer line yet failed to address risks in a timely manner.
The suit stems from the January 19, 2026, rupture of a 72-inch section of the Potomac Interceptor sewer line in Montgomery County near the Chesapeake and Ohio Canal National Historical Park. An estimated 240 million gallons of raw sewage discharged over eight days into the Potomac River and its tributaries.
“Millions of gallons of raw sewage in the Potomac River does not just disappear, it damages ecosystems and harms communities, and it demands accountability,” said Attorney General Brown. “DC Water knew this aging infrastructure was corroding, yet it delayed repairs and failed in its duty to protect this treasured waterway, failures that we allege constitute gross negligence. We are going to court to make sure they make it right for Marylanders.”
“The Potomac River belongs to the people of Maryland, and we expect it to be fully restored to health,” said Maryland Department of the Environment Secretary Serena McIlwain. “The utility must take full responsibility for the damage caused and take immediate and lasting action to prevent future spills. The river is part of our identity, our economy, and our way of life.”
The complaint accuses DC Water of violating state water pollution laws through unauthorized discharges. Maryland seeks civil penalties of up to 10,000 dollars per day for each violation, reimbursement for all environmental testing and cleanup costs, compensation for the lost value of the state’s natural resources, and a court order to permanently stop future unauthorized sewage discharges.
The Potomac Interceptor, more than 50 years old, carries wastewater from parts of Maryland and Virginia to the Blue Plains Advanced Wastewater Treatment Plant in Washington, D.C. Reports indicate DC Water had identified corrosion issues and planned reinforcements years earlier, but construction faced repeated delays tied to federal environmental reviews by the National Park Service.
On the same day, the U.S. Department of Justice, on behalf of the Environmental Protection Agency, filed a separate civil complaint in federal court alleging DC Water and the District of Columbia violated the Clean Water Act. That suit also cites failure to properly operate and maintain the sewer system to prevent untreated sewage from entering the Potomac River.
“As cities grow and infrastructure ages, cities must invest in their wastewater system to prevent such catastrophes,” said Principal Deputy Assistant Attorney General Adam Gustafson of the Justice Department’s Environment and Natural Resources Division. “This complaint seeks to secure DC Water’s commitment to properly maintain its foundational sewage infrastructure.”
DC Water issued a statement acknowledging the lawsuits and emphasizing its work with the National Park Service since 2018 on assessments, environmental reviews and emergency repairs. The utility said it will renew requests for streamlined environmental reviews to accelerate rehabilitation of the interceptor. It noted a previous request for a categorical exclusion for the section was not approved.
The spill prompted recreational water advisories across Maryland, Virginia and the District of Columbia. Testing later showed improving water quality, and advisories for portions of the Potomac in Prince George’s and Charles counties were lifted in early March 2026 after bacteria levels declined.
Southern Maryland residents rely on the Potomac River for recreation, fishing and as part of the broader Chesapeake Bay watershed. The river forms the western boundary of Charles County and influences water quality downstream in St. Mary’s and Calvert counties. Local officials and environmental groups monitored the spill closely due to potential impacts on shellfish harvesting, boating and tourism in the region.
The January rupture occurred along Clara Barton Parkway in an area managed by the National Park Service. Emergency repairs included a bypass system to reroute flow around the damaged section. Remediation efforts continued into April 2026.
Maryland’s lawsuit highlights the broader challenges of aging infrastructure in the Washington metropolitan area. The Potomac Interceptor spans 54 miles and handles up to 60 million gallons of wastewater daily. A 2024 assessment reportedly rated the failed section and nearby portions at elevated risk levels on a one-to-five scale.
The state’s action seeks to hold DC Water accountable for costs incurred by Maryland agencies in testing, monitoring and responding to the contamination. Exact figures for those costs were not specified in the complaint filing.
Environmental advocates, including the Potomac Riverkeeper Network, have called for stronger oversight and faster infrastructure upgrades. The group conducted independent sampling that detected elevated fecal bacteria in the river and tributaries in the weeks following the rupture.
The dual lawsuits represent coordinated federal and state efforts to address the spill’s consequences and prevent recurrence. Both complaints emphasize the need for proactive maintenance of critical sewer lines, particularly those located on or near sensitive federal lands and waterways.
Court proceedings are expected to address the extent of damages, the timeline of known risks, and required corrective actions. No trial date has been set.
Southern Maryland communities near the Potomac continue routine water quality monitoring through state and local programs. Residents can check current advisories through the Maryland Department of the Environment website.
The incident has drawn attention to the intersection of urban infrastructure, environmental protection and interjurisdictional responsibilities in the National Capital Region. Officials stress that full restoration of affected river sections will require sustained investment and collaboration.
