Significant Progress Made to Reinforce Downstream Section of Damaged Potomac Interceptor

March 07, 2026
geopolymer downstream

Significant Progress Made to Reinforce Downstream Section of Damaged Potomac Interceptor

  • As emergency repairs continue, today marks 27 days, nearly one month, with no overflow reaching the Potomac River. The last release that entered the river was February 8.
  • Crews are making significant progress to reinforce the downstream section of pipe from the collapse site and completed 240 linear feet of geopolymer overnight. Crews are working to apply another layer of geopolymer today. The material is similar in strength to concrete and when applied restores the structural integrity of the pipe.
  • Completing the geopolymer on the downstream section of pipe is the last major step in the emergency repair.
  • DC Water crews are working on clearing trees and brush in Area 1, closest to the collapse site, as part of the environmental rehabilitation work. They will also be installing silt fences and performing erosion and sediment control.
  • After an area is cleared, annual rye seed, straw, and coir matting are being applied for soil stabilization.
  • Residents and community members who would like to provide feedback on the Environmental Rehabilitation Plan will now be able to contact us to fill out a form through our dedicated webpage for the Potomac Interceptor Repair.
  • Geopolymer work was completed yesterday on the upstream section of the damaged pipe, covering more than 300 linear feet. This marked the halfway point in the emergency repair.
  • Once the emergency repair is completed, the flow will be restored to the Potomac Interceptor and the bypass pumping system deactivated. Work continues concurrently on the environmental rehabilitation. Daily water quality sampling also continues.

crews doing soil stabilization

Water Quality Sampling Results

Fluctuations in water quality are influenced by factors such as weather events, river flow, runoff, pollutants, releases of combined overflows, and other sources discharging into waterways. Given these variables, measurements taken much further downstream cannot be attributed solely to this incident.

For the Potomac River, historical water quality data shows E. coli levels may vary from a range as low as 10 MPN/100mL to as much as 5,000 MPN/100mL on a given day. A more detailed explanation is posted on the District Department of Energy and Environment (DOEE) website at doee.dc.gov/release/potomac-interceptor-update-and-faqs.

As of March 4, two new sampling locations have been added at Sycamore Island and Lock 6. Sample results from February 23 - present. Past results may be found here.

For quality assurance purposes, lab results are unavailable on weekends and will be posted on the following Monday, excluding holidays.

graphic of water quality testing

 

Latest News

A section of the canal where the soil has been removed
  • Crews are close to completing the removal of remaining soil from Locks 11 to 13 in the section of the C&O Canal that was used as an emergency bypass after the collapse of the Potomac Interceptor sewer ...
Excavation site outside the I-495 Beltway showing section of the PI

Crews completed cleaning on Lock 11 of the C & O Canal as prescribed by the National Park Service, with soil removal also nearing completion within the lock area. Tree removal is also underway, after DC Water received the permits to move forward as part of the site preparations for the long-term accelerated rehabilitation of more than 2700 linear feet of the Potomac Interceptor sewer line that had been previously planned.

Photo of long stretch of C & O Canal with soil removed

DC Water has excavated a section of the Potomac Interceptor along Clara Barton Parkway, outside the I-495 Beltway as part of the accelerated rehabilitation of more than 2700 linear feet of the interceptor that was previously planned. As part of the long-term rehabilitation project, crews are beginning to remove trees which is necessary to construct a bypass chamber that will divert wastewater around sections of the pipe while they are being rehabilitated.

Upcoming Meeting

Board of Directors Meeting

April 24, 2023

Monday 9:00 AM

Announcement

The shields for the tunnel boring machine Mary being lowered by cranes into the shaft
DC Water Earns Prominent Award for Sustainable Finance Leadership through Green Bonds

Recognition highlights DC Water’s commitment to environmental stewardship during Earth Month

DC Water has been honored with the “Green Bond of the Year – US Muni Bond” Award by Environmental Finance, a leading industry publication. This achievement celebrates DC Water’s leadership in sustainability and its dedication to responsible municipal financing.

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
May 5, 2026
Tuesday, 1:00 PM

Upcoming Events

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.