New York City is known for its high quality tap water, but where exactly does it come from? The short answer is, the NYC watershed! In fact, New York has 19 reservoirs to thank for its excellent drinking water quality.

Located in southeastern New York State, the NYC watershed supplies 1.2 billion gallons of unfiltered, potable water each day! The watershed has a total storage capacity of 550 billion gallons and some water bodies are located over 125 miles from the city.

The NYC Water Supply System is split up into three individual water supplies, 1) the Catskill/Delaware Water Supply System from the Catskill and Delaware Watersheds, 2) the Croton Water Supply System from the Croton Watershed, and 3) the Groundwater Supply System in southeastern Queens.

In this post, we’ll take a closer look at some of the history and fun facts behind these water supply systems and each reservoir!

The Catskill/Delaware Water Supply System

The Catskill/Delaware Water Supply System provides 90% of NYC’s drinking water, and it is made up of the following reservoirs:

1. Ashokan Reservoir – “Ashokan” means “Place of Fish” and is home to both coldwater and warm water fish, which include Brown and Rainbow Trout, Smallmouth Bass, and White Perch.

2. Boyds Corner Reservoir – This reservoir was originally part of the Croton Water Supply System. Water from Boyds Corner flows through the Delaware Aqueduct to the Rondout Reservoir.

3. Cannonsville Reservoir – During its construction, the town of Cannonsville and 4 other towns were condemned and flooded, requiring 941 people to relocate. 

4. Kensico Reservoir – The Kensico Dam, which impounds the Kensico reservoir, is on the National Register of Historic Places as part of the Bronx River Parkway Reservation.

5. Neversink Reservoir – This is the highest city reservoir with a spillway elevation of 1,440 feet above sea level.

6. Pepacton Reservoir – This is the largest in volume among the NYC Water Supply reservoirs, holding more than 140 billion gallons of water! (For comparison, the Jacqueline Kennedy Onassis Reservoir holds approximately 1 billion gallons of water.)

7. Rondout Reservoir – This reservoir serves as a central collecting point for the Delaware Water Supply System, receiving water from the Pepacton, Cannonsville, and Neversink Reservoirs.

8. Schoharie Reservoir – Formed by the Gilboa Dam, the Schoharie Reservoir is the northernmost reservoir in the City’s water supply system.

9. West Branch Reservoir – In addition to supplying water to NYC, this reservoir also receives water pumped in from the Hudson River during drought periods.

The Croton Water Supply System

The Croton Water Supply System feeds the remaining 10% of NYC’s drinking water, and it is made up of the following reservoirs:

10. Amawalk Reservoir – Before this north central Westchester County reservoir was placed into service in 1897, the original village of Amawalk was flooded, forcing its residents to relocate.

11. Bog Brook Reservoir – This Putnam County reservoir has a watershed drainage basin of just 4 square miles and serves as a storage reservoir for the larger East Branch Reservoir. 

12. Cross River Reservoir – This reservoir is located in northeastern Westchester County and is stocked annually with over 6,000 brown trout. It’s common to catch brown trout weighing over 5 pounds!

13. Croton Falls Reservoir – This reservoir has 3 basins that are divided by Routes 35 and 36. The reservoir’s water flows among the basins via culverts under the roadways. 

14. Diverting Reservoir – This reservoir holds 900 million gallons of water at full capacity, making it the smallest reservoir by volume, and the only one of New York City’s water supply reservoirs below 1 billion gallons in capacity. 

15. East Branch Reservoir – This reservoir is one of two double reservoirs in NYC’s system and is connected to the Bog Brook Reservoir by a 1,778-foot long tunnel. (The Croton Falls and Diverting reservoirs make up the 2nd double reservoir.)

16. Middle Branch Reservoir – Looking to catch a tiger muskie? Middle Branch Reservoir is stocked annually with 1,000 tiger muskies, which are notoriously difficult to catch.

17. Muscoot Reservoir – To make room for this reservoir, the Village of Katonah was moved south to its present location, requiring over 50 buildings to be relocated using rolled logs pulled by horses.

18. New Croton Reservoir – This reservoir is the last stop for water in the Croton Watershed before emptying into the Hudson River.

19. Titicus Reservoir – The eastern end of this reservoir is fed by the Titicus River, which begins more than five miles away in Ridgefield, CT. 

The Groundwater Supply System in Queens

Perhaps lesser known, NYC also owns a system of 67 wells and 43 well stations, formerly privately owned by ​​Jamaica Water Supply Company. The supply system has not been in operation since 2007 and was closed due to severe water-level declines and saltwater encroachment as a result of rapid urbanization. 

Thirsty for more water-related knowledge? Check out this post about watersheds. Also, have you ever wondered which city has the best tap water?

Interested in watershed monitoring and measuring environmental pollutants in your community? Temboo would love to work with you. Please contact us to learn how we can help!