Critical Repairs Complete on Potomac Interceptor Sewer Line at Dulles

July 30, 2026
Photo of inside Potomac Interceptor at Dulles showing newly lined tunnel
First of four emergency repairs on Potomac Interceptor finished

DC Water has finished the first of four emergency repair projects on the Potomac Interceptor sewer line. Crews completed work today to strengthen a 600-foot section of pipe at Dulles International Airport.

Work began in June after new inspections found serious damage inside the 54-mile sewer line. The damage included corrosion, worn concrete, and exposed steel supports. Crews repaired a 175-foot section of the 42-inch pipe with a strong, concrete-like lining. The final step in repairs used a cured in place liner It’s a flexible liner inserted into the pipe and hardened in place to form a new pipe within the existing one. Together, these repairs restored the pipe to like-new condition.

The Dulles site is one of four Potomac Interceptor locations DC Water identified for emergency repair. The other sites are at Broad Run in Loudoun County, Pennyfield Lock in Potomac, Maryland, and Clara Barton Parkway at the Maryland-D.C. line.

“Completing the first emergency repair on the Potomac Interceptor is an important milestone as we work to address aging sewer infrastructure,” said Matthew Brown, interim CEO and general manager of DC Water. “This work helps protect public health, the environment, and the reliability of a critical sewer line. With this first repair now complete, we continue to make steady progress on both these emergency repairs and our long-term rehabilitation of the Potomac Interceptor.”

After the pipe repairs, DC Water will install a new manhole at the Dulles site. Crews will then begin cleanup and restore the area. That work should finish by early September.

Emergency repairs continue at the three remaining locations.

Pennyfield Lock

  • Critical 175-foot pipe section structurally reinforced
  • Site preparation work underway for slip lining where a new pipe will be installed within the existing pipe

Broad Run

  • Temporary bypass pumping system installed
  • Pipe lining work expected to start in the next two weeks

Clara Barton Parkway at the Maryland-D.C. line

  • Clearing and tree removal complete
  • Temporary bypass pumping system under construction

DC Water is also making progress on the long-term repair near Rock Run along Clara Barton Parkway. This is where part of the sewer line collapsed in January. Crews are building a large temporary pumping system to move wastewater safely around the repair area. The system includes three pipelines, each more than 2,700 feet long.

Later this fall, crews will begin slip lining the damaged pipe. Slip lining means crews will place new pipe sections inside the old pipe. This will create a stronger pipe that better resists corrosion.

The repairs are part of DC Water’s $625 million, 10-year Potomac Interceptor Rehabilitation Program. The program is included in the Authority’s Capital Improvement Program. For the latest information on current repair projects, visit dcwater.com/potomacinterceptor.

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Photo of inside Potomac Interceptor at Dulles showing newly lined tunnel

First of four emergency repairs on Potomac Interceptor finished

DC Water has finished the first of four emergency repair projects on the Potomac Interceptor sewer line. Crews completed work today to strengthen a 600-foot section of pipe at Dulles International Airport.

Picture of repaired segment before the geopolymer work and after the work is done

Crews also reach a major milestone near Dulles International Airport as the next phase of repairs begins this week

DC Water has completed the first major step in emergency repairs to a 175-foot section of the Potomac Interceptor near Pennyfield Lock in Potomac, Maryland. Crews added a new, stronger lining inside the pipe after inspections found serious wear and damage. The work is part of ongoing repairs to 1,700 linear feet of pipe near Pennyfield Lock. Work began on Friday to apply geopolymer, a concrete-like material, inside the pipe. With the new lining complete, crews are preparing for the next phase of work for the remainder of the pipe segment.

image of clara barton parkway with lane closure marked in red

Beginning this week and continuing through mid-August, DC Water will temporarily close one lane overnight on Clara Barton Parkway at the Maryland-D.C. border. The closures are needed so crews can ...

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