New York City drinking water supply and quality report 2022
In 2022, New York City’s water supply system delivered over one billion gallons of safe drinking water daily to more than 8.8 million NYC residents and one million people in nearby counties. The system, which serves nearly half of New York State, relies on 19 reservoirs and three controlled lakes in a 2,000-square-mile watershed.
The Catskill/Delaware supply, providing 97.5% of the water, is disinfected with chlorine and UV light, while the Croton supply, providing 2.5%, is filtered and similarly disinfected. Both supplies are treated with phosphoric acid, sodium hydroxide, and fluoride.