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.