Maryland Supporting Regional Response to Potomac Interceptor Break Since January to Restore Service and Keep Our Waterways Protected
Baltimore, MD (February 20, 2026) — On January 19, a section of the Potomac Interceptor—a large sewer pipe that is owned and maintained by D.C. Water—experienced a breach along the Clara Barton Parkway in Montgomery County, Maryland. Since the breach, the State of Maryland has been engaged in a supportive capacity, working across multiple State agencies and with local and federal partners, to restore service to the interceptor and ensure the health and safety of Marylanders.
“The Potomac Interceptor has been under federal jurisdiction since the 1960s and is still today overseen by the EPA. The incident occurred on National Park Service property and the District of Columbia and the federal government maintain primary responsibility for repair and cleanup operations,” said Governor Wes Moore. “Maryland agencies have been and will remain in close coordination with our partners in the District of Columbia and Virginia. We will continue to support our neighbors by monitoring the environmental impacts of the break.”
The failed section of sewer pipe is 72 inches in diameter. D.C. Water estimates that approximately 240 to 300 million gallons of wastewater spilled into the Potomac as a result of the break. Wastewater has since stopped flowing into the Potomac, with no wastewater from the break entering the Potomac since Super Bowl Sunday. Through D.C. Water, crews accessed the damaged section, began repairs, and are working to provide long-term solutions that reduce the risk of future spills.
Maryland has been engaged since the beginning of the incident in mid-January and will remain engaged in a supportive and interagency response to the incident.
Maryland Department of the Environment
The Maryland Department of Environment is leading the state’s response and is in close coordination with D.C. Water and the U.S. Environmental Protection Agency, who are responsible for the maintenance and monitoring of the Potomac Interceptor and have been engaged in emergency repairs and bypass operations since mid-January.
The department is coordinating among state, local, and federal partners and facilitating regular site visits to oversee containment activity in the Potomac and continues to assess the extent of the environmental damage caused by the incident. A water monitoring plan—coordinated between D.C. Water, D.C. Department of Energy and Environment, and the Maryland Department of the Environment—has been implemented. Though fluctuations in water quality may be influenced by a number of factors in addition to the spill, daily water sampling generally shows decreased bacteria levels over time and distance from the spill site.
MDE’s Water and Science Administration is responsible for regulating shellfish harvesting waters. This effort has three parts: 1) identifying and eliminating pollution sources, 2) collecting water samples for bacteriological examination; and 3) examining shellstock samples for bacteriological contamination and chemical toxicants. Out of an abundance of caution, the department closed a small portion of the Potomac River. The closed portion of the river does not impact shellfish harvest in other areas—including other areas of the Potomac that are approved or conditionally approved for shellfish harvest.
Oysters currently being sold on the market that come from the Chesapeake Bay meet National Shellfish Sanitation Program standards and are not coming from the closure area on the Potomac River. Each bushel of Maryland-harvested oysters currently being sold includes a tag indicating where they were harvested from and are tracked to ensure food safety standards are met.
For up-to-date information about Maryland’s response in support—including environmental impacts, response actions, and water testing results from D.C.Water—visit the Maryland Department of the Environment’s Potomac Interceptor update page. The Maryland Department of the Environment is committed to a sustained, long-term engagement to ensure public health is protected and the spill’s environmental impacts are fully remediated.
Maryland Department of Health
The Maryland Department of Health is monitoring for any potential impacts to human health, working in coordination with Montgomery, Prince George’s, Charles, and St. Mary’s counties. Montgomery, Prince George’s and Charles counties have issued advisories, including:
Avoiding contact with the water or shore line of the impacted area;
Avoiding consumption of any food or water from the impacted area;
Keeping pets away from the impacted area;
Avoiding flushing wipes or grease down any pipes; and
Washing hands and skin should they come into contact with the impacted area.
If individuals come into contact with the impacted area and experience vomiting, diarrhea, a rash, or skin irritation after exposure, they are advised to contact their health care provider immediately.
Additional public health guidance, including updated advisories, may be issued as more information becomes available.
Maryland Department of Natural Resources
The Maryland Department of Natural Resources is beginning to evaluate potential impacts to fish, shellfish, and other wildlife now that ice has largely cleared from the Potomac River and downstream waterways.
The department is also coordinating with the Maryland Department of Health and the Maryland Department of Environment to distribute information to watermen about ongoing shellfish harvesting area closures,which are issued by the Maryland Department of Environment. The three agencies are coordinating closely to ensure that Maryland’s oyster-growing waters meet health and safety standards for shellfish harvesting under the National Shellfish Sanitation Program. The program ensures federal, state, and local agencies test shellfish growing waters regularly and oversee harvesting and processing to ensure oysters are safe to eat.
Maryland Department of Agriculture
The Maryland Department of Agriculture remains in close communication with agricultural producers and seafood stakeholders to ensure timely updates regarding water quality advisories and shellfish harvest restrictions. While the department does not oversee wastewater infrastructure or environmental remediation, the department works alongside partner agencies to help protect Maryland’s agricultural economy, including aquaculture and oyster operations, should impacts arise.
Oysters harvested from the Chesapeake Bay and other tributaries have not been affected by the spill. As a protection to consumers, all shellfish are tagged by harvesters and dealers as required under the National Shellfish Sanitation Program. Tags include the date and location of harvest and, in Maryland, can only come from approved or conditionally approved waters.
Maryland Department of Emergency Management
The department stood up the Potomac Interceptor Coordination Task Force and is coordinating operational activities between the Maryland Department of the Environment, Department of Health, Department of Natural Resources, and Department of Agriculture.
The department’s Maryland Business Emergency Operations Center has also been monitoring the impact on Maryland businesses. Local businesses that may have been impacted by the spill are encouraged to complete the department’s Business Damage Assessment Survey.
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