Uploaded November 2025 | Updated September 2026, 4 hours ago

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DC Water celebrated another major step forward in the Potomac River Tunnel Project with the blessing of tunnel boring machine (TBM) “Mary.”

In this short video, see key moments from the ceremony and learn how this new tunnel will help capture harmful combined sewer overflows before they reach our waterways. This effort is part of DC Water’s long-term commitment to modernizing infrastructure and improving water quality across the District. #DCWater