The primary drinking water supply of Boston, the Quabbin Reservoir is Massachusetts’ largest inland body of water, and is also one of the largest manmade public water supplies in the United States. Created in the 1930’s in the Swift River Valley, it required four towns to be relocated, and covers 39 square miles. The Quabbin consists of 181 miles of shoreline and 412 billion gallons of water. It is fed from three branches of the Swift River and seasonally by the Ware River. After leaving the reservoir, water is transported through one of two aqueducts, the Cosgrove or Wachusett, and then treated at the John J. Carrol Water Treatment Plan at Walnut Hill in Marlborough. Water is then piped to storage tanks before making its way to more local municipal delivery points and then into homes.