Massive Sewage Spill Pollutes Potomac River; Water Testing, Containment Efforts Underway

WASHINGTON — A ruptured sewer line has sent millions of gallons of untreated wastewater into the Potomac River, prompting emergency containment efforts and ongoing water quality testing, officials said.

A section of the aging Potomac Interceptor sewer main collapsed late last week near Clara Barton Parkway in Montgomery County, Maryland, releasing an estimated 60 million gallons of raw sewage per day into the river, authorities said. The pipe normally carries wastewater from communities in Virginia and Maryland to the Blue Plains Advanced Wastewater Treatment Plant in Washington, D.C.

At the beginning of the spill on Jan. 21, a Facebook post from Potomac Riverkeeper Dean Naujoks stated that “Roughly 60 million gallons of raw sewage per day has been discharging into the Potomac River as a result of an interceptor line that broke Monday.” You can view the full video of the spillage here.

During the video, Naujoks described the conditions at the scene: “Oh, my God, the smell is horrific… It’s such high concentrations of sewage that just grabbing a sample is a public health risk.”

Emergency crews from D.C. Water and partner agencies have worked around the clock to install industrial pumps and establish a temporary bypass system that diverts wastewater around the damaged section of pipe. The bypass became operational this week, allowing much of the flow to be rerouted through a dry stretch of the Chesapeake & Ohio Canal and back into the sewer system.

According to D.C. Water, as of Jan. 25, work has been done to drain the remaining wastewater. Once conditions allow, crews will then be able to isolate the damaged section, expose the pipe and begin repairs to restore the sewer main section that was damaged.

Despite progress, some wastewater continues to escape near the rupture, and crews say it will take additional time for full containment and to excavate and inspect the collapsed segment. Officials have not yet provided an estimate for when permanent repairs will be completed.

Health And Environmental Concerns

Environmental groups, including the Potomac Riverkeeper Network, have been collecting water samples and conducting preliminary testing.

In a recent Facebook post on Jan. 26, the Potomac Riverkeeper Network said water testing from the Lockhouse 10 sewage spill shows what it called a catastrophic threat to human health and the Potomac River. PRKN President Betsy Nicholas said E. coli levels measured “nearly 12,000 times what authorities limit for human contact,” adding that “almost 300 million gallons have entered the Potomac River” and that “the long-term impact cannot be overstated.”

Potomac Riverkeeper Dean Naujoks said samples taken directly from sewage discharging from the broken interceptor pipe near Cabin John measured “4,884,000 most probable number (MPN) for E. coli, which is 11,900 times higher than the 410 MPN limit for safe human contact.” Testing at the Lockhouse 10 public river access showed E. coli levels “7,000 times above the 410 limit,” while samples collected roughly four miles downstream at Fletcher’s Cove measured “60 times higher than the 410 standard.” By comparison, upstream testing at Old Angler’s Inn measured “4.1 MPN for E. coli,” which Naujoks said ensured water upstream from the spill “is safe and clean for human contact.”

Naujoks blamed aging infrastructure for the spill, saying “infrastructure failure is at the root of this disaster,” and called it “one of the largest sewage spills in U.S. history.” He added, “The vile and putrid smell from the torrent of sewage discharging to the Potomac River for eight straight days is one of the most disturbing things I have ever seen in 25 years as a Riverkeeper,” warning that “the potential health risks at this level and the long-term impacts to the river are hard to imagine.”

Public health officials and environmental advocates warn that contact with contaminated water poses significant risks. Elevated levels of bacteria such as E. coli and other pathogens are commonly present in untreated sewage, and authorities have advised people and pets to stay out of the river and avoid contact with visible wastewater.

Fish kills and other indicators of ecological stress have been reported by monitoring groups, and concerns about the broader impact on aquatic life and downstream waterways remain.

Drinking Water Not Affected, Officials Say

D.C. Water and regional partners emphasize that the spill does not affect public drinking water supplies, which are drawn from separate systems upstream of the rupture. Intake points for drinking water were not impacted, and authorities say treatment plants continue to operate normally.

Aging Infrastructure Under Scrutiny

The incident highlights the vulnerability of aging water infrastructure in the region. The Potomac Interceptor, installed in the 1960s, had been identified as in need of rehabilitation, and a multiyear, multimillion-dollar upgrade project was already underway. D.C. Water officials say they will review the causes of the rupture and accelerate repairs where possible.

Public Response And Next Steps

Local and federal agencies, including the Environmental Protection Agency and the National Park Service, are coordinating with state and utility partners to monitor water quality, assess environmental damage and oversee cleanup efforts. Additional water sampling and testing will continue in the coming days to better understand the spill’s impact and guide any needed public health alerts.

Residents with concerns or reports of exposure to contaminated water have been urged to contact D.C. Water’s Customer Care team at (202) 354-3600 (Monday through Friday, 8 a.m. to 5 p.m.) or D.C. Water’s 24-hour Command Center at (202) 612-3400.

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