Bi-County East and West Water Tunnel

Prince George and Montgomery, MD


Washington Suburban Sanitary Commission



The Bi-County East and West Water Tunnel supplies potable water to Montgomery and Prince George’s Counties in Maryland.  The tunnel, located in heavily weathered rock up to 120 ft below the I-495 Beltway around Washington, DC, was constructed by drilling through the rock and constructing a cast-in-place concrete liner.  When the main riser of the new tunnel failed during initial acceptance tests, the owner retained SGH to investigate.