UPDATE: Cleaning Continues in Preparation for Emergency Repairs to Damaged Potomac Interceptor Section; No Overflows to River in 18 Days

February 26, 2026

Potomac Interceptor Repairs Update
February 26, 2026

  • No overflows have entered the Potomac River in 18 days, with the last release to the river February 8. 
  • Crews continue work to clean the remaining debris upstream and downstream of the damaged Potomac Interceptor Pipe.
  • A rock and debris dam that had been blocking the pipe has been removed, but some large rocks and boulders remain in other sections of the pipe and may require additional excavation to remove. 
  • Cleaning continues to remove the soil, muck, debris and other loose materials inside the pipe. Once all the material is cleared, a CCTV inspection will be performed to provide a full assessment inside the pipe prior to emergency repairs beginning.
  • The next step will be to pressure wash the inside of the pipe in preparation for the emergency repair, which could begin as early as next week.
  • The repair involves spraying on geopolymer, a material as strong as concrete and more resistant to sewer gases, that will strengthen and rehabilitate approximately 500 linear feet of the pipe upstream and downstream of the failure.
  • Progress continues and the emergency repair remains on target to be completed around mid-March.

DC Water is committed to protecting public health and safety and ensuring the environmental restoration and remediation of the impacted areas. 

Water Quality Sampling Results

DC Water is performing daily water quality sampling. It’s important to note that historically the E. coli levels in the Potomac and Anacostia rivers vary widely from day to day. This is reflected in recent sampling results when stormwater runoff from rain and snow impacting water quality. 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

Below are the results of sampling during the period from February 16 – present. Past results may be found on our dedicated Potomac Interceptor Response page

graphic with water quality sampling results

For more information about the ongoing response and repair efforts on the Potomac Interceptor go to dcwater.com/potomac-interceptor-collapse.

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.