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Dalecarlia Treatment Plant
U.S. Army Site
One of the more "recent" additions to the Washington Aqueduct, this treatment plant was built to accommodate the increasing population of the city in the 1920s. A rapid-sand filter plant was completed in 1926; since then, additional filtering and chemical treatment facilities have been added. Numerous large diameter pipelines send purified water to the District and across the Potomac to consumers in Virginia.
In 1993, a serious warning was issued for bacterial contamination of drinking water in the District and Virginia. The Army Corps of Engineers spent more than $75 million on maintenance, including dredging the Dalecarlia reservoir, replacing filter beds, and installing automatic chemical feeders.
The system, which uses gravity to move water 12 miles from Great Falls to the District of Columbia, is owned and operated by the U.S. Army Corps of Engineers and has been in continuous use ever since it opened more than a century ago. It is listed as a National Historic Landmark. The Union Arch Bridge, which carries a portion of the aqueduct, is also listed as a Historic Civil Engineering Landmark.
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Contact Information
U.S. Army Corps of Engineers
5900 MacArthur Blvd., N.W.
Washington DC 20016
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