A record-setting sewage spill in the Potomac River has exposed decaying infrastructure that experts fear could fail again, in a red flag for the uniquely vulnerable drinking water supply in the nation’s capital.
The spill is a potent reminder of the threat of aging water and sewer pipes across the nation, which have been underfunded for years and are unlikely to get more funding under the Trump administration. In Washington, the stakes are especially high because the city and some suburbs rely exclusively on one source — the Potomac River — for drinking water.
While President Donald Trump has fixated on the spill and directed EPA to help with cleanup, his administration last year proposed drastic cuts to EPA water and sewer funds. Now, over a month after the spill occurred and even as the river shows signs of recovery, there are other weak spots in the 54-mile sewer line that held together during the spill but might not next time.
Crews are installing temporary reinforcements in the riskiest areas, but a permanent fix will take several months, raising questions about whether the sewer system will hold up in the interim — and what happens if it doesn’t.
“We were very fortunate that the collapse occurred downstream from the primary drinking water intakes,” said Michael Nardolilli, executive director of the Interstate Commission on the Potomac River Basin, a regional agency that protects the river. “It’s better to be lucky than good, but there’s only so much luck that can go around here.”
The spill began Jan. 19, when the Potomac Interceptor sewer line collapsed near Cabin John, Maryland, releasing over 243 million gallons of untreated waste into the river.
It’s one of the worst raw sewage releases in U.S. history.
Built in the early 1960s, the Potomac Interceptor transports tens of millions of gallons of sewage daily from communities as far west as Dulles International Airport to the Blue Plains Advanced Wastewater Treatment Plant in southeast Washington. At least three other segments of the line, much of which runs parallel to the river, have been identified as in need of repairs.
Washington has roughly 24 to 48 hours of water available in storage in the event of a severe drought or potential future spill. Congress has funded a study to identify backup water sources, but the effort was recently scaled down due to a new Army Corps of Engineers policy.
Within five days of the spill, crews working in freezing temperatures installed a bypass system to divert sewage into the C&O Canal, a historic waterway that runs parallel to the river and is managed by the National Park Service.
That has kept sewage from continuously flowing into the river since Feb. 8, but also created what environmentalists describe as an open-air sewer in the canal. The bypass system is expected to be deactivated by mid-March.
At a hearing Monday of the Washington Committee on Transportation and the Environment, members of the Council of the District of Columbia noted that the spill could have easily been worse if it had happened in another spot. DC Water has been working for years on a $625 million project to rehabilitate the entire interceptor sewer line due to previously identified weaknesses.
“There were so many worse locations where this could’ve taken place where it would, to this day, still be pumping [wastewater] into the river,” Charles Allen, a member of the council, said during the hearing.
Aside from the portion of pipe that collapsed, one area in need of repair is a 3,000-foot segment that crosses the Potomac near Great Falls, Maryland. DC Water initiated plans to replace the crossing, which is just feet away from a major drinking water intake, in early 2025. A utility spokesperson did not respond to a question about the status of that effort.
Two other pipe segments close to the spill site also need to be replaced, DC Water CEO David Gadis said during Monday’s hearing. Over the next few weeks, the utility will be strengthening that 1800-foot section of the line with geopolymer as a temporary fix, with a permanent repair to be done in the “spring to fall,” Gadis said.
This year’s spill wasn’t the first time that part of the interceptor collapsed. Another portion in Fairfax County failed in February of 2024, causing a much less severe spill that did not reach the Potomac.
An ‘X factor’
DC Water has hired a third party to determine the root cause of the latest spill, with results expected in a few weeks, Gadis said. But there are already theories as to what went wrong.
When the Potomac Interceptor was installed around 1962, construction crews placed large boulders from the area’s famously rocky terrain, rather than soil, on top of some of the line. To DC Water’s surprise, a 30-foot-long boulder pile was found inside the pipe after the spill.
Those rocks, which may have been placed on other portions of pipe, put heavy pressure on the infrastructure. One government official aiding in the response described them as the “likely X factor that broke the camel’s back.”
“That’s a unique factor, that literally tons and tons of boulders were placed on top of the pipe, and over time, pipes corrode,” said the official, who was granted anonymity because they were not authorized to speak publicly.
While the boulders are an unusual issue, they underscore the reality that most water and sewer infrastructure in the eastern U.S. was built over 50 years ago and is nearing the end of its useful life. Many communities have put off needed investments and repairs because of the cost.
In the 1960s, about 60 to 70 percent of investments in water infrastructure were funded by the federal government, said Darren Olson, chair of the Committee on America’s Infrastructure for the American Society of Civil Engineers. Today, the federal government picks up the tab for less than 10 percent of costs, while sewer system failures are on the rise, he said.
“There are roughly 1.8 million miles of sewer throughout our country that’s been installed in various locations and climates,” Olson said. “When you think about the sheer magnitude of that infrastructure, it almost gives you pause to think about what’s needed to install it and maintain it.”
Washington Mayor Muriel Bowser has requested federal funding to cover the cost of the sewage spill, estimated at around $20 million. So far, Federal Emergency Management Agency has issued an emergency declaration, which provides more limited aid — up to $3.75 million — compared to a major disaster.
More federal dollars could go a long way toward accelerating repairs to the Potomac Interceptor, said Steven Bieber, water program director for the Metropolitan Washington Council of Governments. DC Water’s $625 million long-term project to fix the line is part of a larger, $10 billion capital improvement plan.
“What we’re hoping to do, working with our congressional delegation, is to see if there’s a way to accelerate those investments,” Bieber said. “So instead of doing [these projects] over five years, you do it over two years, as a hypothetical example.”
EPA has been aiding in the response, focusing on “monitoring DC Water’s work in managing the bypass, reconstructing the Potomac Interceptor, and remediating environmental impacts,” agency spokesperson Jacob Murphy said.
EPA has had inspectors on the ground at the collapse site daily, even before Bowser requested federal help, Murphy added. But agency officials were not present at two community meetings that DC Water held last week for members of the public.
“The agency is helping determine how federal resources can expedite and/or strengthen DC Water’s work response and recovery work,” Murphy said in an email.
A ‘scaled-back’ study
The cleanup and repair work comes as efforts to identify a backup drinking water source for the Washington region recently hit a setback.
Most major cities, like Philadelphia, New York and Los Angeles, have at least two distinct sources of drinking water, whereas Washington only has one, according to the Army Corps. The agency manages the regional drinking water supply for over a million people.
Washington House Delegate Eleanor Holmes Norton (D) has secured $2.3 million for the corps to conduct a study identifying alternative water sources. But the Army Corps instituted a new policy last year requiring all water infrastructure studies to be completed within three years and capping the cost at $3 million.
The policy also mandates that at least 35 percent of projects identified in studies be fully designed before they can advance toward construction. The shift is meant to speed studies along and ensure projects aren’t funded without a full understanding of what will be built, officials have said.
But it means that several ideas previously considered to shore up Washington’s water supplies are now off the table. The Army Corps and its local sponsor, the Metropolitan Washington Council of Governments, are narrowing in on a more limited solution: increasing water storage at an existing reservoir.
That would provide an additional 12 hours of storage, but it is only a partial fix, said Sharon Nichols, a spokesperson for Norton.
“The Army Corps has now scaled back the study drastically,” Nichols said in an email. “Expansion wouldn’t solve the problem of finding a backup supply in case the Potomac or the reservoir are contaminated.”
Cynthia Mitchell, a spokesperson for the Army Corps’ Baltimore district, said 12 hours of extra water supply would still provide “invaluable time” for local, state and federal entities to respond to a water emergency. But she said the agency is still weighing all options.
“We realize that this alternative improves, but does not resolve, the systemic source water or storage problem for the region,” Mitchell said in an email. “We are committed to exploration of those more complex, whole-system solutions, while also rapidly delivering engineering solutions that provide the greatest benefits to the nation today, not years into the future.”
