New York City Water Supply System

The New York City water supply system is a network of aqueducts, reservoirs and tunnels that supplies fresh water to New York City from three major sources, the Croton, Catskill and Delaware systems, stretching as far as one hundred twenty five miles to the north, making it one of the most extensive municipal water systems in the world. Its treatment process is simpler than that of most other American cities because its watersheds are unusually well protected, including through the Land Acquisition Program, under which the city's Department of Environmental Protection has purchased or protected more than one hundred thirty thousand acres of watershed land since 1997. That protection has let the system qualify for a partial exemption from federal and state filtration requirements, saving billions of dollars in construction and ongoing operating costs, and the system's topography allows about ninety five percent of the water to reach the city by gravity alone.