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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There is no active spill or overflow. Work to strengthen the pipe to begin soon.

Today, DC Water completed construction on a temporary bypass system as part of sewer repairs on the Potomac Interceptor near Pennyfield Lock in Potomac, Maryland. Crews turned on the pumps and successfully tested the system. With the bypass now ready, it will allow us to begin the emergency repairs inside the pipe by carrying the wastewater around the repair area.

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Today, DC Water broke ground on the Piney Branch Tunnel, the final major tunnel in our Clean Rivers Project. This work will help keep sewage and trash out of local waterways and make Rock Creek, the Potomac River, and the Chesapeake Bay cleaner for our community.

When we finish the Piney Branch Tunnel, it will hold at least 4.2 million gallons of rainwater and wastewater during heavy storms. Instead of overflowing into Piney Branch, that water will go to the Blue Plains Water Resource Recovery Facility, where it will be treated.

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April 24, 2023

Monday 9:00 AM

Announcement

DC Water Officials with NPS and ANC commissioners doing ceremonial groundbreaking
DC Water Breaks Ground on Piney Branch Tunnel, Final Phase of DC Clean Rivers Project

Today, DC Water broke ground on the Piney Branch Tunnel, the final major tunnel in our Clean Rivers Project. This work will help keep sewage and trash out of local waterways and make Rock Creek, the Potomac River, and the Chesapeake Bay cleaner for our community.

When we finish the Piney Branch Tunnel, it will hold at least 4.2 million gallons of rainwater and wastewater during heavy storms. Instead of overflowing into Piney Branch, that water will go to the Blue Plains Water Resource Recovery Facility, where it will be treated.

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