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.

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DC Water has outlined its next steps to complete the environmental cleanup and its plan for continued water quality monitoring this summer, as part of the ongoing response to January’s failure in the Potomac Interceptor sewer pipeline. The plan, submitted to the Maryland Department of the Environment (MDE), is supported by extensive data from hundreds of samples.

crews removing soil in C & O Canal

Work continues to remove the remaining soil between locks 10 and 12 of the C & O Canal which was used as an emergency bypass while the Potomac Interceptor was repaired. Crews area also removing plants, trees, and shrubs in preparation for the long-term rehabilitation of the Potomac Interceptor.

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DC Water has nearly completed construction site preparation for the Piney Branch Tunnel project, including tree removal, and installation of fences, erosion and sediment controls, utilities, and ...

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April 24, 2023

Monday 9:00 AM

Announcement

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Piney Branch Parkway Temporary Closure and Relocation

DC Water has nearly completed construction site preparation for the Piney Branch Tunnel project, including tree removal, and installation of fences

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