UPDATE: Excavation Site Extended Around Damaged Section of Potomac Interceptor to Access Rock Blockage

February 23, 2026
Photo of extended excavation site with trench boxes

Potomac Interceptor Repairs Update
February 23, 2026
 

  • The excavation around the damaged section of pipe has been extended and trench boxes installed to provide shoring and stability. This doubles the size of the excavated area, to connect the collapse site with a downstream access point to the Potomac Interceptor.
  • The newly excavated section will allow crews to reach an area of the pipe believed to be blocked by large rocks and debris. The section, adjacent to the collapse site, is too compromised for crews to safely complete this work from inside the pipe. Instead, crews plan to remove the crown of the pipe section to access the rocks and debris for removal.
  • On-site coordination continues with U.S. Army Corps of Engineers (USACE) to assist with stormwater management to protect pumping operations.
  • Cleaning efforts continue to remove muck and debris upstream from the damaged section and downstream portions. 
  • Development of the Environmental Restoration Plan is ongoing in coordination with Environmental Protection Agency (EPA), National Park Service, Maryland Department of the Environment, USACE, and the District Department of Energy and Environment with some preliminary mediation efforts underway.
  • DC Water is partnering with USACE and EPA to divert runoff away from the contaminated land and install “catchment basins” below street drains and in the creek to capture runoff that may carry residual wastewater contaminants to the Potomac River. 

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. 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 from the one-week period of February 16-22, 2026. Past results may be found on our dedicated Potomac Interceptor Response page.

Graphic with water quality results

For more information about the ongoing repair efforts go to dcwater.com/Potomac-interceptor-collapse.

Latest News

Photo of soil removal and excavation

DC Water and its contractor have removed all the soil down to the clay liner between locks 12 and 13, marking 50% completion of the canal clean-up. Soil removal between Locks 13 and 14 was completed earlier this month. Meanwhile, clean-up efforts continue between locks 10 and 12, with sludge removal complete and soil removal now underway.

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 ...

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.

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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.