DOEE Potomac Interceptor Update: Friday, February 13:

This page will be updated every Friday with the latest water quality monitoring results and new information.  

Key Updates: 

• DRINKING WATER IS SAFE AND IS NOT IMPACTED BY THE SEWAGE RELEASE. 

Frequently Asked Questions – Sewage Spill from the Potomac Interceptor Collapse 

What Happened? 

On Monday, January 19, 2026, a section of a 72” diameter sewer line collapsed near the Clara Barton Parkway in Montgomery County, Maryland. The sewer line, called the Potomac Interceptor, carries up to 60 million gallons of wastewater daily from Virginia and Maryland to Blue Plains Advanced Wastewater Treatment Plant. 

This collapse means that a significant quantity of untreated sewage flowed into the Potomac River.  

What Does This Mean for DC? 

DC DRINKING WATER IS A SAFE AND SEPARATE SYSTEM AND IS NOT IMPACTED BY THE SEWAGE RELEASE. 

However, because the Potomac River flows downstream from Maryland into Washington, the portion of the river in the District is affected by this spill. 

Until we know more, all DC residents and visitors should avoid unnecessary contact with water from the Potomac River. Avoid fishing. Keep pets away from the Potomac River. 

A major concern with untreated sewage is the presence of a bacteria commonly called “E. coli.” "E. coli, when it reaches certain levels, is dangerous to human beings. Sewage also contains other bacteria, viruses, and harmful chemicals. 

Aside from its risk to humans, raw sewage is also harmful to the environment. 

What Should I Do to Be Safe? 

Most importantly, drinking water is safe and is not impacted by the sewage release.  The flow of sewage into the Potomac River has occurred downstream of any drinking water intake from the river.   

• Vulnerable Populations: Immunocompromised individuals, parents of newborn infants, and others who may be especially at risk from infection should exercise special caution around the river. However, to repeat, all individuals should currently avoid contact with the river. 

Can I Swim in the River? 

Swimming is already prohibited in District waters. You should not swim in the river. 

What Should I Do If I Come into Contact with Sewage? 

Wash the affected area as soon as possible. If you think you have become sick from sewage, contact your health provider. Symptoms can vary, but may include diarrhea, fever, cramps, nausea, coughing, vomiting, headache, weakness, loss of appetite, and fatigue.  

Who Is Responsible and What’s Being Done? 

The District of Columbia Water and Sewer Authority (DC Water) is a public utility responsible for water and sewage in the District of Columbia. DC Water is currently working on measures to contain the spill and repair the pipeline. 

The DC Department of Energy and Environment (DOEE) is the DC Government agency responsible for environmental and energy programs in the District of Columbia. DOEE is working to monitor impacts from this spill in the District, and will also monitor the long-term impacts to fish, wildlife, and the river. 

Right now, dozens of local, state, and federal agencies are working collaboratively to monitor the progress of repairs and impacts on the downstream community. 

How to Understand the Test Results Below 

E. coli is typically used as an indicator for all types of bacteria and viruses that can be harmful to human health. Simply put, E. coli measurements are used as a standardized test to determine if the water is safe. 

There is natural bacteria present in all bodies of water, and low levels are considered safe. The U.S. Environmental Protection Agency, along with the District of Columbia, Maryland, Virginia, and other states, use a consistent standard level to determine if a body of water is safe for recreation. This level is 410 MPN/100 mL for E. coli, which means 410 colonies of E. coli bacteria in a 100 mL sample of water. 

If testing numbers show levels below 410 MPN/100ML (marked in green), then the water is considered safe for recreation according to DC and federal standards. However, due to the continued uncertain nature of the spill, and the fact that weather conditions (such as ice on the river) may impact test results, DOEE recommends continued precautions and avoiding contact with the Potomac River until these results can be confirmed by longer-term sampling. 

What Do the Latest Water Monitoring Results Show? 

DOEE’s water quality monitoring team is collecting weekly samples from the Potomac and Anacostia rivers. Results from these samples are posted in the table below. DOEE will be conducting weekly sampling, posted on Fridays. 

In addition to DOEE’s results, DC Water is conducting daily testing at several sites in the Potomac, with their results posted here: News | DC Water. 

Linked here are ongoing testing results from DC Water, Potomac Riverkeeper, and DOEE, along with the locations of the testing sites. 

If E. Coli Levels Are Within Safe Recreational Levels (Below 410 MPN/100 ML), Why Is The District Advising The Public To Avoid Contact With The River And To Avoid Fishing? 

Due to the continued uncertain nature of the spill, and the fact that weather conditions (such as ice on the river) may impact test results, DOEE recommends continued precautions and avoiding contact with the Potomac River until these results can be confirmed by longer-term sampling. 

DOEE wants to ensure we are measuring consistently safe results before revising this guidance. 

Map of Sampling Stations for DC Water (blue dots) and DOEE (pink dots) 

What Is District Government Doing to Ensure the Safety of the Public and Assess Impacts to the Environment? 

Multiple state and federal agencies are cooperating to oversee the repair operations and protect the environment, including the Maryland Department of Environment (MDE), the U.S. Environmental Protection Agency (EPA), the District Department of Energy and Environment (DOEE), and National Park Service (NPS). DOEE and EPA are inspecting the bypass weekly to ensure that DC Water is doing everything possible to prevent overflows, contain and mitigate any overflows that occur, as well as plan for comprehensive environmental restoration. 

On January 29, 2026, DC Water began daily bacteria monitoring at 6 locations. DOEE has increased the frequency of E. coli monitoring from monthly to weekly and is exploring partnerships to add more locations. Early data has shown significant bacteria reductions in the 2 weeks after the bypass was installed. DOEE is conducting weekly bacteria monitoring on both the Potomac and Anacostia Rivers. 

DOEE is planning fish and wildlife surveys beginning in the spring (some as early as late February) that will help indicate if the sewage spill has larger impacts.   

What Are the Likely Short- and Long-Term Impacts of the Sewage Spill on the Potomac River?  

Aside from its risk to humans, raw sewage is harmful to the environment. Solids in sewage can smother aquatic habitats. Plants and animals can suffer infections from the bacteria, viruses and other pathogens; they can also suffer from acute toxicity in sewage chemicals. In the days following the spill, several fish kills were reported but not verified, and icy conditions prevented immediate surveying.  

What Is the Natural Flow of the River? Will it Clean Itself? 

Long-term impacts are still being evaluated. However, the natural flow of the river will help to mitigate impacts from the spill over time.    

• Water Quality: Models estimate that water takes approximately 3 weeks to flow through the District’s portion of the river (roughly from Chain Bridge to the I495 Wilson Bridge). As temperatures warm bacteria levels may fluctuate as sewage from the collapse that is trapped in ice will be released into the water column, along with snowmelt and urban runoff that carries additional pollution from other sources. 

• Fish: DOEE has not received any reports of fish kills in the District. Anglers and the general public who observe a fish kill (50 or more dead fish floating on the surface of the water), should contact DOEE’s Fisheries and Wildlife Division at (202) 535-2260 with the following information: exact location of the floating fish and date, time, and the extent of the fish kill observed. DOEE biologists will monitor fish populations across the District throughout the spring, summer, and fall as a part of our regular fisheries surveys. 

• Wildlife: DOEE and its partners have not received any reports of sick, injured, or dead wildlife associated with areas in the District downstream from the spill. Members of the public who observe sick or injured wildlife should call City Wildlife at (202) 882-1000 (between 9 am - 5 pm daily) or Brandywine Valley SPCA at (202) 888-7387 (after 5 pm). Members of the public should report dead wildlife to DOEE’s Fisheries and Wildlife Division at (202) 535-2260 with the following information: exact location of the dead wildlife and date, time, and number of animals observed. DOEE biologists will monitor wildlife populations across the District throughout the spring, summer, and fall as a part of our regular wildlife surveys. 

What Work Is Being Done to Repair the Sewer Line? 

DC Water publishes daily updates on response operations related to infrastructure repair, containment of the sewage, environmental monitoring, and restoration planning. Read their updates here: News | DC Water 

How will the Potomac River and the C&O Canal be restored? 

DC Water has hired an environmental company to begin planning how the spill site, the C&O canal, and other areas damaged by the spill are restored. DOEE, EPA, MDE, and National Park Service will be working with DC Water and their contractors to ensure that the remediation meets regulatory requirements.