Long-Term Rehabilitation Work on Potomac Interceptor Continues in Preparation for Construction

April 21, 2026
Photo of long stretch of C & O Canal with soil removed
  • DC Water has excavated a section of the Potomac Interceptor along Clara Barton Parkway, outside the I-495 Beltway as part of the accelerated rehabilitation of more than 2700 linear feet of the interceptor that was previously planned.
  • As part of the long-term rehabilitation project, crews are beginning to remove trees which is necessary to construct a bypass chamber that will divert wastewater around sections of the pipe while they are being rehabilitated.
  • Soil removal is now 55% complete in the C & O Canal. Work continues to remove the soil down to the clay liner on the remaining sections of the canal between locks 10 and 12.
  • Cleaning is complete on the historic canal’s locks 11, 12, and 13 utilizing NPS prescribed methods.

Water Quality Sampling

Daily water quality testing continues to show E. coli levels within the typical range for recreation, with normal historical fluctuations attributed to rain, heat, stormwater runoff, and other known environmental factors. See the District Department of Energy and Environment webpage for more details.

Ongoing sampling is precautionary and intended to address community concerns, ensuring the highest standards of public health and safety.

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.

Results April 13 – present below: (past results can be found here)

graphic of water quality sampling results

You can find more information about the environmental rehabilitation, get the latest news and information, and results of all the water quality testing on our Potomac Interceptor Response page.

Latest News

Photo of long stretch of C & O Canal with soil removed

DC Water has excavated a section of the Potomac Interceptor along Clara Barton Parkway, outside the I-495 Beltway as part of the accelerated rehabilitation of more than 2700 linear feet of the interceptor that was previously planned. As part of the long-term rehabilitation project, crews are beginning to remove trees which is necessary to construct a bypass chamber that will divert wastewater around sections of the pipe while they are being rehabilitated.

The shields for the tunnel boring machine Mary being lowered by cranes into the shaft

Recognition highlights DC Water’s commitment to environmental stewardship during Earth Month

DC Water has been honored with the “Green Bond of the Year – US Muni Bond” Award by Environmental Finance, a leading industry publication. This achievement celebrates DC Water’s leadership in sustainability and its dedication to responsible municipal financing.

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DC Water issues the following statement in response to the complaints filed by the Maryland Office of the Attorney General and the Department of Justice on behalf of the U.S. Environmental Protection ...

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April 24, 2023

Monday 9:00 AM

Announcement

The shields for the tunnel boring machine Mary being lowered by cranes into the shaft
DC Water Earns Prominent Award for Sustainable Finance Leadership through Green Bonds

Recognition highlights DC Water’s commitment to environmental stewardship during Earth Month

DC Water has been honored with the “Green Bond of the Year – US Muni Bond” Award by Environmental Finance, a leading industry publication. This achievement celebrates DC Water’s leadership in sustainability and its dedication to responsible municipal financing.

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