Dean Naujoks of the Potomac Riverkeepers Network collecting water samples from the sewage spilling out from the Potomac Interceptor pipe northwest of D.C. (Dean Naujoks)
As the season’s first serious winter storm was bearing down on D.C. last week, another significant threat was rapidly flowing into the Potomac River: human shit, and lots of it.
A break in a six-foot diameter pipe – carrying sewage from as far away as Dulles to the Blue Plains Advanced Water Treatment Plant in D.C. – led to more than 200 million gallons of sewage flowing directly into the Potomac River just north of the city.
“This is unprecedented,” said Dean Naujoks of the Potomac Riverkeepers Network, adding that it is among the country’s biggest sewage spills ever.
And while D.C. Water – which operates the 54-mile-long pipe – has put a temporary fix in place, there are concerns about the long-term impacts on the health of the Potomac, a richly symbolic regional river that local jurisdictions have been struggling to clean up for decades. But there’s at least one relief: drinking water hasn’t been impacted.
Here’s what else you need to know.
What happened?
The initial break in the Potomac Interceptor pipe – which carries 60 million gallons of sewage a day – was reported on January 19. It occurred on a portion of the tunnel just inside the Beltway, some four miles northwest of D.C. along the C&O Canal.
It wasn’t initially clear where all that sewage was going. Some advocates say D.C. Water told them that it was pooling in the canal, but it quickly became apparent that it was actually flowing directly into the Potomac River. Authorities say about 40 million gallons a day overflowed from the pipe and that it’s likely that most of it made its way to the river.
D.C. Water quickly got to work on a temporary fix, installing a series of pumps upstream of the broken pipe to funnel some of the sewage into an empty portion of the canal, where it would be redirected back into the pipe below the break. The bypass was activated on January 24, six days after the break was reported.
“Most of the flow is successfully being diverted,” D.C. Water spokeswoman Sherri Lewis told The 51st over email. “At the collapse site itself we can visually see the drop in wastewater escaping and are beginning to do some initial assessment. We expect to achieve full containment using the bypass.”
As of Tuesday, though, the bypass wasn’t catching all of the sewage spilling out of the broken pipe, though by a day, later D.C. Water reported that it had added additional capacity that significantly reduced overflow.
Still, Ward 6 Councilmember Charles Allen, chair of the transportation and environment committee, says there was a lack of transparency from the D.C. Department of Energy and Environment amid the initial break.
“While responding to a sewage release of this size is burdensome and our drinking water source is secure, I have been frustrated by the lack of information provided to the public about the public health and environmental risks posed by more than a week of raw sewage polluting our region’s primary waterway,” he wrote in a letter to both the agency on Wednesday.
When will it be fixed?
A massive sewer pipe running from parts of Virginia and Maryland into D.C., the Potomac Interceptor dates back to the early 1960s, and it is showing its age. D.C. Water inspected the length of the pipe between 2011 and 2015 and found that “the majority of the pipe segments show signs of corrosion.”
The utility is in the midst of a 10-year, $625 million plan to rehabilitate the pipe. In fact, work was completed in September on a portion just upstream of where the break occurred.
Lewis says that engineers are still deciding the best course for the “complex and time-intensive” repairs ahead, which has been complicated by the current cold weather (they may be able to use some of the materials from the aforementioned project, though).
Excavation around the broken pipe started on Wednesday, but D.C. Water said in a Facebook post that a timeline can’t be determined until it's fully inspected.
What are the impacts on the Potomac?
The Potomac Riverkeepers Network tested water from the river downstream from the river late last week, and it isn’t mincing words: they call the current impact “catastrophic.”
Downstream of the break, measurements for E.coli bacteria show contamination nearly 12,000 times what authorities limit for human contact, according to PRKN President Betsy Nicholas. Further into D.C., the numbers were better, but still bad: 60 times what’s safe for human contact.
While this doesn’t impact D.C.’s drinking water (since it’s drawn from further upstream in a separate system), it has sparked warnings about humans or animals coming into contact with the water.
The D.C. Department of Energy and the Environment “strongly recommends that residents and their pets continue to avoid direct contact with the Potomac River, such as fishing, until the situation is fully resolved and bacteria levels are reported as safe.” (Naujoks thinks public health agencies in D.C., Maryland, and Virginia should be doing more to spread this type of message.)
If there’s any silver lining to be found, it may be the timing of the spill.
“We're lucky because the sewage spill happened when recreational and biological activities are at their low point,” says Hedrick Belin, president of the Potomac Conservancy, which advocates for cleaning up the river and releases an annual report on the Potomac’s overall health.
Still, Naujoks worries about the possible unknowns to come. “Are there going to be algae blooms and fish kills later down the road, because this ice and snow may be locking some of this sewage into the water column and leading to a potential delayed release?” he asks.
Stepping back, Belin says the spill highlights that while the health of the Potomac River has been improving due to efforts in and around D.C., it remains vulnerable. (In its 2025 report, the group ranked the river’s health at a B-, where it’s held for a decade.)
But the recent spill “should be seen as a wake-up call reminding us what it takes to keep the river clean,” Belin says. “Sewer overflows are happening in Rock Creek and other tributaries of the Potomac all the time, dozens, dozens of times a year. And that's why the Potomac remains unsafe for many to swim in.”
With your help, we pursue stories that hold leaders to account, demystify opaque city and civic processes, and celebrate the idiosyncrasies that make us proud to call D.C. home. Put simply, our mission is to make it easier — and more fun — to live in the District. Our members help keep local news free and independent for all:
