Sewage Continues to Flow into the Potomac River

On January 19^th, 2026, a massive pipe that moves millions of gallons of sewage ruptured and sent wastewater flowing into the Potomac River northwest of Washington, D.C that has repair crews scrambling. Nine days later, DC Water reports that they are  nearing “full containment” of the sewage spill. Meanwhile, 40-60 million gallons of sewage flowed into the Potomac River each day.

The spill was caused by a 72-inch (183-centimeter) diameter sewer pipe that collapsed late Monday, January 19^th shooting sewage out of the ground and into the river. DC Water spokesperson John Lisle said the utility estimates the overflow at about 40-60 million gallons each, but it’s not clear exactly how much has spilled into the river since the overflow began.

The spill occurred in Montgomery County, Maryland, along Clara Barton Parkway, which hugs the northern edge of the Potomac River near Chesapeake and Ohio Canal National Historic Park. Crews are removing lock gates on the C & O Canal and are setting up pumps to divert the sewage into the canal, rerouting it away from the river and back into the sewage system downstream. This is reported to be an enclosed section of the canal, thank goodness.  

DC Water teams and contractors are working around the clock maintain the bypass system day and night to keep the pumps and equipment operating, even as temperatures remain well below freezing. The pumps require frequent cleaning and maintenance because sewage containing fats, oils, grease, wipes, and other debris in the wastewater cause blockages. When blockages occur, pumps must be temporarily taken offline for service, which reduces system capacity until the issue is resolved.

Additional pumps have arrived and are being installed to add redundancy and increase overall pumping capacity.  This added capacity will help further reduce the wastewater levels and support progress towards achieving full containment. To help this along, residents in Fairfax, Loudoun, and Montgomery counties that are served by the interceptor are encouraged to avoid flushing wipes or disposing of grease down drains, which helps support ongoing emergency operations. By the way, none of those items should be flushed anyway.

DC Water emphasizes that there is no impact to the drinking water supply from this overflow. The Washington Aqueduct’s main intakes for drinking water are upstream from the break.

The bypass system, installed with cooperation from the National Park Service, uses a contained section of the C & O Canal running about 2,700 feet to carry wastewater around the damaged section of pipe and back into the Potomac Interceptor further downstream. Monitoring shows that flow rates are increasing by about 40 million gallons a day after re-entering the sewer system. All the flows then are directed to DC Water’s Blue Plains Advanced Wastewater Treatment Plant.

A U.S. Environmental Protection Agency spokesperson said the agency was coordinating with DC Water, the Maryland Department of the Environment and other federal, state and local authorities to assess the impact on the environment from the Potomac Interceptor sanitary sewer overflow. The federal agency oversees DC Water’s sewer operations under a 2015 federal consent decree.

An EPA survey of wastewater infrastructure needs from 2022 estimated that the District of Columbia needs roughly $1.33 billion to replace or rehabilitate structurally deteriorating sanitary or combined sewers within the next 20 years. DC Water had allocated $625 million in its Capital Improvement Program for projects to rehabilitate the Potomac Interceptor over the next 10 years. They just did not do it soon enough, and this little disaster will and repair will probably end up increasing the cost significantly and moving up the schedule.

Water delivery and sewage removal systems have a long life span, they are just pipes, pumps and valves, but the life span is not infinite. This sewer interceptor dates from the 1960’s so it is about 60 years old. We reward short sighted behavior. In order to have cheaper water and sewer, a near realistic replacement cost schedule was not built into the customer rates for almost 80 years. 

DC Water systems are the oldest in the region.  The system was mismanaged by the city for years and by 1996 some portions of the water delivery system were 100 years old and the sewage system was almost the same age. The water and sewage rates in place in  Washington DC   by 1996 covered the costs to purchase water from the Washington Aqueduct, deliver the water and treat the sewage and replace 0.33% of the system each year. That meant a system with an expected life of 80 years had a planned replacement life of 300 years, an unrealistic and irresponsible repair and replacement rate.

In 2012 that began to change after increasing incidence of failures in the system and DC Water announced that they had tripled the replacement rate to 1% (with of course the increase in water rates) so that in 100 years the system would be replaced. It is likely, given the age of the water system in Washington DC the increase in replacement rate was probably necessary to address what was failing each year. Broken water mains or sewage pipes in Washington DC region are so common they are only mentioned in traffic reports unless they are spectacularly large.

from DC Water