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New York City Watershed

Ashokan Reservoir in Ulster County, New YorkFinal Revisions issued to the 2007 Filtration Avoidance Determination

The New York State Department of Health, in consultation with USEPA Region 2, issued revisions to New York City’s 2007 Filtration Avoidance Determination (FAD) on May 7, 2014.  This final action follows release of the draft revisions in August 2013 and opportunity for public review.

NYSDOH FAD Web Page Exit EPA disclaimer

The New York City watershed covers some 1,900 square miles in the Catskill Mountains and the Hudson River Valley. The watershed is divided into two reservoir systems: the Catskill/Delaware watershed west of the Hudson River and the Croton watershed east of the Hudson. Together, the systems deliver approximately 1.4 billion gallons of water each day to nearly 9 million people in New York City and Westchester Orange, Putnam and Ulster counties. 

The Catskill Water Supply System, completed in 1927, and the Delaware Water Supply System, completed in 1967, provide about 90 percent of New York’s water supply. The combined Catskill/Delaware watershed cover 1,600 square miles. Drinking water from the Catskill/Delaware system is of high quality and is delivered to New York consumers unfiltered.

The Croton Water Supply System was completed prior to World War I. Consisting of 10 reservoirs and three controlled lakes, the Croton system has the capacity to hold 95 billion gallons of water, and normally provides 10 percent of New York City's daily water supply. The Croton Watershed covers approximately 375 square miles east of the Hudson River in Westchester, Putnam, and Dutchess counties and a small section of Connecticut. The Croton water supply will begin to be filtered sometime in 2014.

On July 30, 2007, EPA, in consultation with the New York State Department of Health (DOH), released its most recent New York City Filtration Avoidance Determination (FAD) for the Catskill/Delaware Water Supply. EPA and DOH determined that New York City has an adequate long-term watershed protection program for its Catskill/Delaware water supply that meets the requirements for unfiltered water supply systems.

On September 26, 2007 EPA transferred the authority to oversee the Catskill/Delaware water supply system to DOH. EPA Region 2 continues to work with New York City and New York State on programs to protect the watershed and to monitor the success of these programs, both from the water quality perspective and from a public health perspective.


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