In March, the beleaguered—some would say besieged—city of Detroit, Michigan announced it would begin shutting off water services to between 1,500 and 3,000 households every week. It seemed impossible at the time but officials quickly made good on the promise. Detroit, the former industrial powerhouse of one of the world’s richest countries, has seen better days. But water is an essential social service, a necessity of life, and the city lies in the middle of the Great Lakes, the world’s largest body of freshwater. How could the taps possibly run dry?