Potomac Interceptor Sewage Discharge

Status Report
The Potomac Interceptor Collapse
Safeguarding Public Health and the Environment
Water Quality Monitoring
Repairs and Cleanup
EPA's Role
Additional Response Information

U.S. Environmental Protection Agency is the lead federal agency in the response to the Potomac Interceptor collapse. This website is being updated with information about the collapse, public health and environmental safety, repairs, environmental cleanup, and EPA’s role.

Status Report

Updated March 30, 2026

EPA Updates

The White House assigned the U.S. Environmental Protection Agency (EPA) as the lead federal agency in response to the Potomac Interceptor (PI) collapse, which resulted in at least 240 million gallons of raw, untreated sewage discharging into the Potomac River. On March 14, fifty-five (55) days after the initial report of the Potomac Interceptor collapse, emergency repairs were completed and flow restored.

In mid-March, EPA assumed responsibility for sampling Potomac River water quality previously conducted by the DC Department of Energy and Environment (DOEE). Water quality samples are being taken by EPA daily, processed, and posted to DOEE’s Potomac Interceptor Monitoring webpage. As the incident shifts toward environmental remediation, EPA’s Fort Meade lab will continue to serve as the home for water quality sampling analysis. EPA is planning to continue water quality sampling through May 1.

EPA completed initial post-remediation soil sampling of Areas 1 and 2 in the week of March 23. Area 4 remediation began on Saturday, March 14 once flow returned. EPA will continue to conduct soil sampling, as needed, until results indicate all sewage impacted soils have been removed.

The Potomac Interceptor Collapse

On January 19, 2026, a portion of a large-diameter sewage conveyance pipe, called the Potomac Interceptor, collapsed. The Potomac Interceptor was originally constructed in the 1960s and today conveys up to 60 million gallons of wastewater daily from parts of Virginia and Maryland to DC Water’s Blue Plains wastewater plant where it is treated and returned to the river. As a result of the collapse, approximately 240 million gallons of raw, untreated wastewater overflowed into the Potomac River before a bypass came online on January 24, 2026. The bypass, constructed by DC Water, redirected the sewage into a secure section of the Potomac Interceptor where was taken to Blue Plains to be treated. Episodic overflows occurred into early February. However, following additional measures to enhance the capacity and operations of the bypass, no additional sewage overflows from the collapse have reached the Potomac River since February 8, 2026. On March 14, emergency repairs were completed and wastewater flow was restored through the Potomac Interceptor, ending temporary use of the emergency bypass.

Safeguarding Public Health and the Environment

The best available information at this time indicates that drinking water is safe for the D.C. metro area and has not been significantly impacted by the Potomac Interceptor collapse. Water that is taken from the river, treated, and distributed as safe drinking water to the D.C. metro area is pulled from the Potomac River upstream of the collapse. Water quality monitoring near and around these intakes shows no signs for concern.

It is important to note that the Interceptor is not the only source of wastewater that affects the Potomac River. Fluctuations in water quality in the river can be driven by wet weather events and wastewater discharges unrelated to the Interceptor Collapse.

Under the Clean Water Act’s framework of cooperative federalism, state and local authorities implement water quality standards and issue advisories to limit public use when necessary. Out of an abundance of caution, Maryland, Virginia, and Washington D.C. initially issued advisories to limit river-based recreation in several parts of the Potomac. The scope of these advisories has been reduced in light of ongoing water quality monitoring (highlighted below) showing that the impact of the spill is relatively localized near the site of the collapse.

The Virginia Department of Health has lifted a recreational health advisory for Virginia residents from the American Legion Bridge (I-495) to Route 120 Chain Bridge.
In Maryland, a recreational health advisory has been partially lifted for Montgomery County.
Washington, DC has lifted its recreational advisory for the Potomac River.
DC Water is continuing to advise the public to avoid any contact with untreated sewage, which remains a risk until the Potomac Interceptor is repaired and cleanup is complete.

Ongoing Water Quality Monitoring

Water quality monitoring of the Potomac River shows that contamination is relatively localized to where the collapse occurred. It’s important to note that historically the E. coli levels in the Potomac and Anacostia rivers vary widely from day to day. Fluctuations in water quality are influenced by factors such as wet weather events, river flow, runoff, pollutants, and other sources discharging into the waterways. On March 16, EPA took over water quality sampling previously conducted by the DC Department of Energy and Environment as part of a planned transition in the ongoing repair and remediation effort. Sampling results will be available on DOEE’s website.

Additional detailed maps and monitoring information is available from:

Repairs and Environmental Cleanup

Visit DC Water’s website for their latest updates on Potomac Interceptor repairs and environmental remediation.

EPA's Role

On February 20, 2026, President Trump approved a Federal Emergency Declaration in response to the Potomac Interceptor collapse. The White House assigned EPA as the lead federal agency. In this role, EPA is coordinating with federal agencies, including the Federal Emergency Management Agency (FEMA), the Department of Homeland Security (DHS), the National Parks Service (NPS), and the Army Corps of Engineers. On February 24, 2026, federal partners and the District of Columbia established a Unified Coordination Group. On March 16, 2026, EPA announced it would assume responsibility for water quality sampling previously conducted by the DC Department of Energy and Environment (DOEE). Water quality samples are being taken by EPA daily, processed, and posted to DOEE’s Potomac Interceptor Monitoring webpage.

Throughout this process, EPA will continue to facilitate open and transparent lines of communication with DC Water, state and local partners, and the public. The agency is committed to coordinating with all federal partners to conduct robust oversight, implement a streamlined and efficient communication strategy to inform the public of important updates, and provide resources to support the completion of repairs and remediation efforts as quickly as possible.