This public-private partnership provides clean drinking water for nine million New Yorkers.

Croton & Catskill/Delaware Watersheds

(What is a Watershed? video produced by Missouri & Mississippi Divide Resource Conservation & Development Inc.)

The New York City (NYC) water supply system is one of the largest surface water storage and supply systems in the world. In the United States, New York City is one of five metropolitan areas still supplying unfiltered surface water to its City residents.

The system reliably delivers more than 1.1 billion gallons of safe drinking water daily to nine million people – this represents nearly half the population of all New York State.

The NYC water supply system consists of three surface water sources:

  • the Croton watershed (375 acres) east of the Hudson River
  • the combined Catskill and Delaware watershed system (1,597 acres) west of the Hudson River.

These watersheds combined drainage area

  • totals 1,972 square miles (about 1.2 million acres)
  • includes 19 reservoirs and three controlled lakes

The East of Hudson Watershed (Croton aerial tour by

  • Is made up of the Croton Watershed and small components of the Catskill and Delaware Watersheds.
  • Is located within parts of New York’s Westchester, Putnam and Dutchess counties and Fairfield County, CT.
  • Includes the original water supply areas for New York City.
  • Croton is suburbanized with remaining areas of farm and forest.
  • The Croton Watershed spans 375 acres, spanning a total of 212,700 acres including the reservoirs.
  • Provides 10% of the City’s daily needs and up to 30% under drought conditions or for other operational demands.
  • A water filtration plant has been built.
  • Contains three controlled lakes:
    1. Kirk Lake
    2. Lake Gilead
    3. Lake Gleneida
  • Contains 13 reservoirs
    1. Amawalk
    2. Bog Brook
    3. Boyds Corner (considered part of Delaware system)
    4. Cross River
    5. Croton Falls
    6. Diverting
    7. East Branch
    8. Kensico (considered part of Catskill system)
    9. Middle Branch
    10. Muscoot
    11. New Croton
    12. Titicus
    13. West Branch (considered part of Delaware system)

The Catskill/Delaware Watershed (Cat/Del aerial tour by

  • Is located within Delaware, Greene, Schoharie, Sullivan, and Ulster counties.
  • Is largely rural and comprised of small to mid-sized dairy, vegetable and mixed livestock farms.
  • Is roughly 75% forested; 85% of those woodlands are privately owned.
  • Spans 1,597 acres.
  • Provides 90% of the City’s daily water needs.
  • Contains six reservoirs:
    1. Ashokan
    2. Cannonsville
    3. Neversink
    4. Pepacton
    5. Rondout
    6. Schoharie

NYC watershed map 2010


Josh Dick - Over the Croton Watershed

Josh Dick - Over the Catskill-Delaware Watershed