<P> The District of Columbia Water and Sewer Authority (i.e. WASA or D.C. Water) is an independent authority of the D.C. government that provides drinking water and wastewater collection in Washington . WASA purchases water from the historic Washington Aqueduct, which is operated by the Army Corps of Engineers . The water, sourced from the Potomac River, is treated and stored in the city's Dalecarlia, Georgetown, and McMillan reservoirs . The aqueduct provides drinking water for a total of 1.1 million people in the District and Virginia, including Arlington, Falls Church, and a portion of Fairfax County . The authority also provides sewage treatment services for an additional 1.6 million people in four surrounding Maryland and Virginia counties . </P> <P> Pepco is the city's electric utility and services 793,000 customers in the District and suburban Maryland . An 1889 law prohibits overhead wires within much of the historic City of Washington . As a result, all power lines and telecommunication cables are located underground in downtown Washington, and traffic signals are placed at the edge of the street . A plan announced in 2013 would bury an additional 60 miles (97 km) of primary power lines throughout the District . </P> <P> Washington Gas is the city's natural gas utility and serves over one million customers in the District and its suburbs . Incorporated by Congress in 1848, the company installed the city's first gas lights in the Capitol, the White House, and along Pennsylvania Avenue . </P>

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