Potomac commuters who use Clara Barton Parkway to reach Washington, D.C., will face overnight lane closures at the Maryland-D.C. border through mid-August as DC Water crews repair a deteriorating section of the Potomac Interceptor sewer line.

DC Water issued the traffic advisory on Wednesday, announcing that one lane will remain open in each direction during the overnight work. Flaggers will direct traffic through the construction zone and drivers should expect short delays.

The advisory does not specify whether closures will occur every night or only on select nights, and it does not list specific hours. DC Water says work will continue through mid-August but has not announced a precise end date.

The closures are part of ongoing work on the 54-mile Potomac Interceptor pipeline, which carries roughly 60 million gallons of sewage daily. The pipe, built in the 1960s and 1970s, catastrophically ruptured near Lock 10 of the C&O Canal National Historical Park in January, spilling more than 200 million gallons of untreated wastewater into the Potomac River over about a week.

DC Water completed emergency repairs at the January collapse site in mid-March. But subsequent surveys revealed additional corroded segments upstream near Pennyfield Lock in Potomac, where crews are slip-lining 1,700 feet of new pipe, with DC Water targeting completion in September. The utility has earmarked $625 million over 10 years to rehab the entire interceptor system, according to information shared at a February community meeting hosted by the West Montgomery County Citizens Association.

The January spill also triggered federal and state legal action. In April, the U.S. Department of Justice and Maryland's attorney general filed separate lawsuits against DC Water. In June, the utility's board removed CEO David Gadis.

"For years, officials knew this pipe was failing. Engineers warned of corrosion. They warned of structural risk," Dean Naujoks, the Potomac Riverkeeper, said in a June 25 press release announcing his organization's motion to intervene in both lawsuits.

DC Water's full advisory, including any updates to closure hours, is posted at dcwater.com/about-dc-water/media/news.