Traffic Advisory: Sewer Rehabilitation Project May Cause Temporary Delays on Clara Barton Parkway

October 17, 2025
Map of construction area on Clara Barton Parkway near I495
Updates Traffic Advisory issued Sept. 8, 2025, to reflect extended work noted in bold

Beginning September 8th, 2025, and continuing through October 10th, 2025, Clara Barton Parkway near the interchange with I-495/Beltway, will be reduced to one lane of traffic from 9:30 a.m. to 2:00 p.m. for a sanitary sewer rehabilitation project. The temporary lane closure is necessary to reline an 800-foot section of the sewer line, known as the Potomac Interceptor.

A temporary lane closure will be required in the same location to install a barrier wall for safety, construction equipment, and additional work on an as needed basis over the duration of the project. Construction is expected to be completed in Spring 2026.  

During construction, drivers may experience delays inbound on Clara Barton Parkway approaching the Beltway and through the work zone. The lane closure will begin prior to the I-495 Beltway ramp to the outer loop and continue just past the underpass. Access to both the inner and outer loop will remain available. Morning commuters traveling toward DC or to the I-495 Beltway are advised to plan for additional traffic and may want to consider alternate routes.

The Potomac Interceptor is a major sewer line that extends from the area around Washington Dulles International Airport to DC Water’s Blue Plains Advanced Wastewater Treatment Facility. The system carries 60 million gallons of wastewater daily from Virginia, Maryland, and DC.

Signage on Clara Barton Parkway will be posted to alert drivers of lane restrictions. DC Water appreciates your patience and cooperation as we complete this critical work to rehabilitate the Potomac Interceptor.

Visit dcwater.com to learn more about the Potomac Interceptor and the work underway to rehabilitate the 54-mile sewer line. This project is part of DC Water’s capital investment in infrastructure improvements to ensure safe, reliable sewer service and wastewater treatment for the region.

 

Latest News

View of Mary at bottom of shaft inside tunnel shown from above

First turn of cutterhead signals the start of excavation for the Potomac River Tunnel Project

In a defining moment for one of the District’s largest infrastructure investments, DC Water has marked its next major milestone in the Potomac River Tunnel Project. The first tunnel boring machine, Mary, has launched her northbound journey breaking through the soil to signal the start of excavation.

With the first turn of Mary’s drill-like cutterhead underground, the machine pushed forward to begin tunneling, representing the transition from years of planning and preparation to active tunnel construction on the $819 million project.

Photo of the vegetation growing back in the culvert area
  • DC Water has completed soil removal, utilizing excavators and manual digging, to expose the clay lining for the C & O Canal between locks 13 and 14. This is the final step in the clean-up process ...
Workers manually removing soil between the locks

Work is progressing on the clean-up for the C & O Canal which was used as a bypass while the Potomac Interceptor was repaired. Workers are focused on removing sludge between locks 11 and 12. Soil removal is also nearly complete between locks 12 and 14, reaching the canal's clay liner. Workers are now manually removing additional materials in some areas.

Upcoming Meeting

Board of Directors Meeting

April 24, 2023

Monday 9:00 AM

Announcement

View of Mary at bottom of shaft inside tunnel shown from above
DC Water Launches Tunnel Boring Machine Mary, Marking Important Step for Potomac River Tunnel Project

First turn of cutterhead signals the start of excavation for the Potomac River Tunnel Project

In a defining moment for one of the District’s largest infrastructure investments, DC Water has marked its next major milestone in the Potomac River Tunnel Project. The first tunnel boring machine, Mary, has launched her northbound journey breaking through the soil to signal the start of excavation.

With the first turn of Mary’s drill-like cutterhead underground, the machine pushed forward to begin tunneling, representing the transition from years of planning and preparation to active tunnel construction on the $819 million project.

Latest Blog Post
A helicopter lowers a drill rig to workers on the Potomac River.
DC Water begins drilling in Potomac River to explore options to rehab underwater sewer line
When one of your major sewer lines runs through the Potomac River, a backhoe and trencher won't do. That's why we've got helicopters carrying a 14-ton drill and workers suspended midair over the Potomac.
Upcoming Meeting
Date
April 15, 2026
Wednesday, 9:30 AM

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.