Sludge Removal Complete between locks 13 and 14, work continues on remaining C & O Canal sections

March 24, 2026
Photo showing work between locks 13 and 14 where sludge has been removed
  • DC Water has completed sludge removal on a section of the C & O Canal between locks 13 and 14, which was used as a bypass to divert wastewater around the collapsed section of the Potomac Interceptor and back into the pipe further downstream. Crews are now constructing an access bridge to this section of the canal to allow soil removal to begin.
  • Work continues to clear sludge and debris from the remaining sections of the canal between locks 10 and 13.
  • Approximately 3100 feet of the canal is being cleaned and the soil removed down to the clay liner. Crews, working in coordination with National Park Service, will then rebuild the canal to NPS’s specifications.
  • DC Water continues working with National Park Service in developing plans to rehabilitate and clean the historic locks.
  • The initial clean-up and temporary stabilization are complete on the areas directly impacted by the overflows, including the drainage channel, Culvert 12 (Rock Run Culvert), the tributary, and portions of the Potomac River and shoreline where the overflow occurred.
  • Beautification and revegetation in these areas is pending results from soil sampling taken by the Environmental Protection Agency to verify clean-up efforts and determine if additional rehabilitation is necessary.
  • As part of the beautification and revegetation, native species will be replanted. Additional native trees will be planted in the fall which is the best time to plant to avoid heat stress during the summer.
  • DC Water is working with Maryland Department of the Environment to establish sediment testing locations and protocols.

Water Quality Sampling Results

It's important to understand that rain, snow, heat, contaminated runoff, and natural sources of E. coli such as wildlife can cause higher bacteria levels in urban rivers such as the Potomac. For this reason, experts recommend avoiding the water for at least 48-72 hours after heavy rain. This is reflected in the data last week, where significant spikes are seen that coincide with heavy rainfall including areas upstream where measurements are unrelated to the overflow event.

As there have been no overflows to the river from the Potomac Interceptor for more than a month prior to completion of emergency repairs, fluctuations in measurements are more likely due to these other known factors.

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.

Sample results from March 16 - present. Past results may be found here.

graphic of water quality sampling

For the latest updates and information, including how to provide feedback on the environmental rehabilitation, go to our dedicated Potomac Interceptor Response page.

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.
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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.