Partial Bypass Expected to Begin as Early as This Weekend

DC Water and its contractor continue to make progress to contain the sewer overflow from a collapsed section of the Potomac Interceptor (PI), a major sewer line along Clara Barton Parkway near 495 in Montgomery County, MD.  As part of that work, crews today are mobilizing equipment, clearing brush and debris, and installing pipes in preparation to bypass the flow around the damaged section of sewer line. Pumps are expected to begin redirecting some of the wastewater as early as this weekend, significantly reducing the sewer overflow entering the Potomac River.

The Potomac Interceptor handles up to 60 million gallons of wastewater every day, moving through a large 72-inch pipe at the site of the break. Multiple high-powered industrial pumps— each pumping seven million gallons a day – will be utilized to reroute the wastewater into a section of the C & O Canal where it can be safely contained and directed back into the sewer line further downstream.

Beginning Thursday, working in conjunction with the National Park Service, work will begin to remove the upper lock gates on the canal at locks 11, 12, 13, and 14 which is necessary to accommodate the bypass. All efforts are being made to balance the need for public health and safety with preserving the integrity of the historic locks and canal as much as possible.

DC Water and its contractor have all available resources committed to containing the overflow with highly specialized equipment being deployed from as far away as Detroit. While a partial bypass is expected as early as this weekend, full containment is expected later next week. Once fully operational, crews will start excavating and inspecting the damaged section of the pipe to develop plans for repairs.

Earlier this week, a section of the 54-mile sanitary sewer line collapsed, sending untreated wastewater into a creek bed and the Potomac River. The pipe carries flow from parts of Virginia and Maryland to the Blue Plains Advanced Wastewater Treatment Plant.

DC Water is in the process of rehabilitating the Potomac Interceptor, as part of a 10-year, $625 million high priority project in the Authority’s Capital Improvement Program. The project will rehabilitate the most vulnerable sections in the aging sewer line, which is more than 60-years old.

Until the bypass is fully operational, and the overflow contained, the public is reminded to avoid contact with untreated sewage as it may carry bacteria and viruses. Anyone who comes in contact with the wastewater overflow should:

• Leave the area immediately.
• Wash exposed skin thoroughly with soap and clean water.
• Disinfect any affected areas or items.
• Do not consume food or water that may have been exposed.
• Seek medical attention if symptoms occur.
• Report exposure to DC Water at (202) 612-3400.

The drinking water supply is completely safe and unaffected thanks to separate systems. The overflow happened downstream from the Washington Aqueduct’s intakes at Great Falls, and intakes at Little Falls have also been closed as a precaution.

The C & O Canal Towpath remains open, and no overflow has reached the towpath. National Park Service staff are monitoring the area for any signs of impact. Neighbors near the affected zone may notice odors from the overflow. In addition, the right inbound lane on the Clara Barton Parkway, just east of the 495 interchange, is closed and may impact inbound rush-hour traffic.

DC Water continues to work with our federal, state, and local partners to ensure public safety and monitor environmental impacts while we work to contain the overflow and begin repairs. We are also monitoring the weather and the potential for significant snow this weekend. Work will continue, however, may be slowed in the event of heavy snowfall.

Anyone with questions or in need of support can reach out to DC Water’s Customer Care team at (202) 354-3600 (Monday–Friday, 8 a.m. to 5 p.m.) or the 24-Hour Command Center at (202) 612-3400.