 It and its six tributary reservoirs—which make up a total surface area of 7.2 square miles (18.6 km²)—supply drinking water to more than 60 percent of the state population, including Providence.The surrounding drainage basin that provides water to the reservoir system covers an area of about 94 square miles (243.5 km²), which includes most of the town of Scituate and parts of Foster, Glocester, Johnston, and Cranston.The Scituate Reservoir is operated by Providence Water Supply Board.