Neversink Reservoir is a reservoir in the New York City water supply system. It is located in the Catskill Mountain town of Neversink in Sullivan County, New York, 75 miles northwest of the City. It is fed by the Neversink River, the longest tributary of the Delaware River. Water collected in the reservoir in turn goes through the Neversink Tunnel …Neversink Reservoir is a reservoir in the New York City water supply system. It is located in the Catskill Mountain town of Neversink in Sullivan County, New York, 75 miles northwest of the City. It is fed by the Neversink River, the longest tributary of the Delaware River. Water collected in the reservoir in turn goes through the Neversink Tunnel a short distance east to Rondout Reservoir to be pooled with that from Pepacton and Cannonsville reservoirs which form the west-of-the-Hudson River components of the Delaware Aqueduct. Together, they provide nearly half of the city's daily consumption.