Located in Delaware County along the southern edge of the State's forever wild Catskill Park, 12 miles south of the Village of Delhi, and more than 100 miles northwest of New York City. Formed by the damming of the East Branch of the Delaware River, which continues west and joins the lower Delaware River. Consists of one basin, approximately 15 miles in length. Holds 140.2 billion gallons at full capacity, which makes it the largest reservoir in the City system by volume. Placed into service in 1955.
The Pepacton is one of four reservoirs in the City's Delaware Water Supply System. As the reservoir with the largest capacity, it normally contributes more than 25% of the total daily water flow into New York City. Water withdrawn from the Pepacton Reservoir enters the East Delaware Aqueduct and flows southeast for 25 miles into the Rondout Reservoir. There it mixes with water from the Cannonsville and Neversink Reservoirs, before heading south via the 85-mile long Delaware Aqueduct, which tunnels below the Hudson River. Pepacton water ordinarily makes its way to the West Branch and Kensico Reservoirs for further settling. After mixing with Catskill system waters in the Kensico, it travels via aqueduct to the Hillview Reservoir in Yonkers, where it enters New York City's water supply distribution system.
The Pepacton watershed's drainage basin is 371 square miles, and includes parts of 13 towns in three counties: Andes, Bovina, Colchester, Delhi, Hamden, Middletown, Roxbury and Stamford in Delaware County; Denning, Hardenburgh and Shandaken in Ulster; and Halcott and Lexington in Greene.