Starting around May 21, 2026, drivers on K Street NW should expect a change in traffic patterns between 29th and 30th Streets NW, beneath the Whitehurst Freeway to support ongoing construction for the Potomac River Tunnel Project.

The active lane closure will shift from the north side to the south side of the roadway to support ongoing jet grouting operations. This process strengthens the ground to prepare for construction below the surface.  This new configuration is expected to remain in place through early August 2026. 

Construction at the site will continue through 2028 as part of DC Water’s long-term Clean Rivers Project, which is designed to reduce sewer overflows into the Potomac River.

What Drivers and Neighbors Should Expect
Date: May 21, 2026 – August 2026 (weather permitting)

• One lane closed 24/7 on K Street NW between 29th and 30th Streets NW 
• Sidewalk closed on the north side of K Street NW
• Bicycle lanes will remain open
• Traffic from the Rock Creek and Potomac Parkway ramp will be directed to turn right onto 29th Street NW

Drivers should plan to allow extra travel time. Traffic controls will be in place to safely guide vehicles, cyclists, and pedestrians through the area. 

Project Details
The Potomac River Tunnel is part of DC Water’s Clean Rivers Project to reduce pollution in local waterways. Each year, about 650 million gallons of untreated sewer overflows enter the Potomac River and Chesapeake Bay, harming water quality and aquatic life.

The 5.5-mile tunnel will capture and redirect this overflow to the Blue Plains Advanced Wastewater Treatment Plant, reducing overflow volume by 93% and the number of occurrences from 74 to 4 times in a typical year.

At K Street and 30th Street NW, crews are building an underground facility to capture flow that would otherwise be discharged into the Potomac River from this location. 

This work is part of a federal consent decree entered by DC Water, the District of Columbia, the US Environmental Protection Agency, and the US Department of Justice, as amended in January 2016. Learn more at dcwater.com/prt.

Contact Us
Project Email: dcpotomacrivertunnel@dcwater.com 
Project Hotline: 202-972-1388 
DC Water 24-hour Emergency: 202-612-3400