Lawsuit claims thousands of owners of vessels and real property harmed during Jan. 19, 2026, overflow of 243 million gallons of raw, untreated wastewater

Following a 243-million-gallon sewage spill into Washington, D.C.’s Potomac River, owners of local property and vessels have filed a proposed class-action lawsuit against District of Columbia Water and Sewer Authority, according to environmental attorneys at Hagens Berman seeking damages for alleged oversight.

The lawsuit was filed March 6, 2026, in the U.S. District Court for the District of Maryland and claims DC Water “failed to implement adequate interim safeguards, emergency preparedness plans, or monitoring protocols to prevent or contain a catastrophic failure in the highest-risk unremediated sections of the system,” despite documented knowledge of system-wide corrosion.

The lawsuit brings claims on behalf of a proposed class of owners of property and vessels in the area of the spill who incurred out-of-pocket costs, business interruption damages, property contamination, cleaning costs or other concrete economic losses. Those affected may contact the firm for more information about their rights.

The firm has litigated claims on behalf of residents facing contaminated water and groundwater, as well as air pollution and various other local environmental issues.

“We believe DC Water has a duty to the residents it serves for what we intend to show amounts to negligence,” said Steve W. Berman, managing partner and co-founder of Hagens Berman. “We expect DC Water will try to play the victim. As we see it, this is an instance of high-risk infrastructure that was operated without reasonable safeguards, not an inevitability.”

“A Failure of Immense Proportions”

DC Water owns, operates and maintains the Potomac Interceptor, which DC Water describes as a regional sanitary sewer system conveying on the order of 60 million gallons of wastewater per day from service areas in Fairfax County and Loudoun County, Virginia and Montgomery County, Maryland, to DC Water’s Blue Plains Advanced Wastewater Treatment Plant in Washington, D.C.

On Jan. 19, 2026, a 72-inch diameter section of the PI collapsed along the Clara Barton Parkway near the Interstate 495 interchange in Montgomery County, Maryland, within the Chesapeake and Ohio Canal National Historical Park near Lock 10.

“The collapse caused massive volumes of raw, untreated sewage to overflow directly into the Potomac River,” the lawsuit states. “DC Water publicly estimated that approximately 243 million gallons of wastewater overflowed from the collapse site, with approximately 194 million gallons occurring within the first five days before bypass pumping operations significantly reduced overflows.”

Independent monitoring by the Potomac Riverkeeper Network and the University of Maryland reported E. coli concentrations at the outflow near Lock 10 exceeding 4,000,000 MPN/100 mL well above the 410 MPN/100 mL primary-contact threshold used by agencies in Virginia, Maryland and the District of Columbia, and consistent with EPA-referenced recreational water quality criteria.

“We seek losses for infrastructure failure, physical contamination and other economic damages for a failure of immense proportions,” Berman said. “DC Water had 10 years to act to prevent this, and paid dearly for that oversight.”

DC Water’s Duty

The lawsuit highlights DC Water’s prior knowledge of infrastructure deterioration, stating, “DC Water had extensive, actual, and documented knowledge of the deteriorated condition of the Potomac Interceptor for over a decade prior to the January 19, 2026 collapse.”

According to the lawsuit, DC Water publicly acknowledged that between 2011 and 2015 it inspected the Potomac Interceptor and that the inspection indicated “the majority of the pipe segments show signs of corrosion.” The PI corridor where the collapse occurred had been under active rehabilitation since September 2025 as part of a rehabilitation project, but the specific section that collapsed had not yet been rehabilitated.

“In response to the inspection findings, DC Water initiated a $625 million, 10-year capital improvement program to rehabilitate the PI’s most vulnerable sections, as part of its broader $10 billion Capital Improvement Program,” the lawsuit states.

Fort Myer Construction Corp. began performing an approximately $9.6 million rehabilitation project using sliplining methods on an approximately 800-foot segment of the PI near I-495 on Sept. 8, 2025. The collapse occurred approximately one-quarter mile from this active work site.

When DC Water and its contractor performed the September 2025 rehabilitation of the adjacent upstream segment, DC Water did not conduct a contemporaneous condition assessment of the pipe section immediately downstream — the section that collapsed on Jan. 19, 2026.

“DC Water’s engineers and contractors were physically present in the immediate vicinity of the section that would fail four months later, performing work on the same pipeline prompted by the same corrosion findings, yet took no documented steps to assess or safeguard the adjacent unremediated section,” the lawsuit states.

The lawsuit brings claims of negligence, private nuisance, public nuisance and trespass and seeks compensatory and injunctive relief on behalf of a proposed class that attorneys say includes thousands of residents.

Find out more about the firm’s lawsuit against DC Water.

About Hagens Berman

Hagens Berman is a global plaintiffs’ rights complex litigation law firm with a tenacious drive for achieving real results for those harmed by corporate negligence and fraud. Since its founding in 1993, the firm’s determination has earned it numerous national accolades, awards and titles of “Most Feared Plaintiff’s Firm,” MVPs and Trailblazers of class-action law. More about the law firm and its successes can be found at hbsslaw.com. Follow the firm for updates and news at @ClassActionLaw.

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The lawsuit brings claims on behalf of a proposed class of owners of property and vessels in the area of the spill who incurred out-of-pocket costs, business interruption damages, property contamination, cleaning costs or other concrete economic losses.