Potomac River Tunnel Project

DC Water’s Potomac River Tunnel Project


The Potomac River Tunnel (PRT) is the next major phase of the DC Clean Rivers Project. The project consists of a large-diameter deep sewer tunnel, diversion facilities, drop shafts, and support structures to capture flows from existing combined sewer overflows (CSOs) along the Potomac River and convey them to the Blue Plains Advanced Wastewater Treatment Plant for treatment.

There are 8 CSO outfall locations on the Potomac River. In a year of average rainfall some 74 CSO events discharge approximately 654 million gallons of CSO into the Potomac. When complete, the PRT is estimated to reduce those events to four and reduce the volume of CSOs by 93% in an average rainfall year.

In 2019, DC Water began design work for the Potomac River Tunnel and in 2024 began mobilization at West Potomac Park. When completed in 2030, the tunnel will improve water quality and aesthetics of the Potomac River for the benefit of all.

Just The Facts
93 %
Reduction
OVERFLOW
To POTOMAC River
5.50
miles
Tunnel Length
18
Feet
Tunnel Diameter
100
Feet
Tunnel Depth
6.50
Years
Construction Duration
819
Million Dollars
Tunnel Cost

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View of the Alexandria Aqueduct
Capital Crescent Trail: Temporary Travel Lane, Trail Detours, and Parking Restrictions

(Washington, DC) –As a part of DC Water’s Potomac River Tunnel Project, temporary traffic lane closures, trail detours, and parking restrictions wi

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