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.

Latest News

Graphic invitation to Community Day on September 19 from 10:30 a.m. t0 3 p.m.

DC Water Opens the West Potomac Park Construction Site to the Public for Tours, Activities and More

Ever wonder what it takes to build a 5.5-mile tunnel beneath the nation’s capital? On Saturday, September 19, DC Water invites the community for a rare opportunity to experience one of the District’s largest infrastructure projects up close and underground.

Photo of manhole entrance withe completed geopolymer

Second of four high-priority repair projects is now complete

DC Water has completed the second of four critical repair projects on the Potomac Interceptor Sewer Line. Crews finished strengthening a 490-foot section of the pipe at Broad Run in Loudoun County today.

Image of Clara Barton Parkway showing lane closure

Beginning this week and continuing through the end of September, DC Water will temporarily close one lane overnight on Clara Barton Parkway at the Maryland-D.C. border. The closures are necessary to allow crews to safely begin geopolymer work, a concrete-like material, applied inside the sewer line as part of emergency repairs to a section of the Potomac Interceptor.

Upcoming Meeting

Board of Directors Meeting

April 24, 2023

Monday 9:00 AM

Announcement

Graphic invitation to Community Day on September 19 from 10:30 a.m. t0 3 p.m.
Go Behind the Scenes at the Potomac River Tunnel Project Community Day

DC Water Opens the West Potomac Park Construction Site to the Public for Tours, Activities and More

Ever wonder what it takes to build a 5.5-mile tunnel beneath the nation’s capital? On Saturday, September 19, DC Water invites the community for a rare opportunity to experience one of the District’s largest infrastructure projects up close and underground.

Latest Blog Post
Emergency supplies arranged on a table, including bottled water, canned food, a backpack, first aid kit, flashlight, phone, medication and other essential items.
Simple Ways to Stay Prepared at Home
A few simple steps can help your household prepare for severe weather and temporary water or sewer service interruptions.
Upcoming Meeting

Upcoming Events

Sep 19
Sep 19

Customer Service Center Announcement

Payment Plan Incentive: provides a credit back of 50% of the last 3 payments made. Eligible participants are residential customers who have had an outstanding balance for 60 days or greater and with an outstanding balance of $500 or more.