New York City Drinking Water Supply and Quality Report 2019
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New York City Drinking Water Supply and Quality Report 2019 Bill de Blasio Vincent Sapienza, P.E. Mayor Commissioner Pepacton Reservoir Vincent Sapienza, P.E. Commissioner Dear Friends: On behalf of my 6,000 colleagues at the Department of Environmental Protection (DEP), I am proud to report that New York City continues to enjoy some of the best tap water in the world. In 2019, we delivered more than 1 billion gallons of clean and delicious drinking water to nearly 10 million people every day. In this report, you will see that New York City's drinking water met or surpassed every national and state standard for quality in 2019. These data are based on over 51,000 samples that were collected by DEP scientists throughout our reservoir system, and at nearly 1,000 street- side sampling stations in every neighborhood across the city. Those samples were analyzed 719,000 times by scientists working in our four water quality laboratories. Robotic monitoring stations on our reservoirs provided another 2 million tests to ensure DEP was sending the best- quality water to New York City at all times. Our drinking water system relies on vast reservoirs, large dams, hundreds of miles of aqueducts, and thousands of miles of water mains. We believe that steady and focused investment in infrastructure is key to the future of New York City. This is why we have more than $20 billion in investments planned over the next decade, to ensure a continuous supply of high- quality drinking water for generations to come. As we end a decade and look forward to the next, I want to thank you for entrusting DEP with your drinking water supply. We take great pride in delivering the best water to millions of New Yorkers every day. Sincerely, Vincent Sapienza, P.E. Commissioner 2 OTSEGO RENSSELAER CHENANGO COUNTY SCHOHARIE COUNTY COUNTY COUNTY ALBANY Oneonta COUNTY Gilboa C D a Catskill/Delaware e t s la k w il a l r e Schoharie S Delhi h Reservoir Watersheds a n d a COLUMBIA k GREENE e COUNTY DELAWARE n COUNTY COUNTY T u Hunter n NEW YORK s n le e i l M 5 Pepacton MASSACHUSETTS 12 Cannonsville Walton Reservoir River Reservoir Downsville Phoenicia Ashokan Esopus Reservoir Deposit Creek West Branch East Delaware Tunnel Delaware Kingston West Delaware Tunnel East Branch Delaware DUTCHESS COUNTY Neversink Hudson Reservoir Rondout ULSTER Reservoir COUNTY Delaware Aqueduct Liberty Poughkeepsie Neversink CONNECTICUT Tunnel SULLIVAN s Ellenville e il COUNTY M 0 0 1 Croton C Croton a t s PENNSYLVANIA Delaware k i l Watershed l A q u e r d e u v River i c R t Lake Boyds Corner k Reservoir Gleneida s n le i Middle i s M r Branch e 5 v Reservoir 7 e PUTNAM Bog Brook N Lake COUNTY Gilead Reservoir ORANGE East Branch COUNTY Kirk Reservoir West Branch Lake Reservoir Croton Falls Diverting Reservoir Reservoir s ile Titicus M 0 Amawalk Reservoir 5 New Croton Reservoir Cross River Reservoir Reservoir H N e Muscoot u d w Reservoir s C o r WESTCHESTER n o o t NEW YORK COUNTY ROCKLAND n NEW JERSEY COUNTY A R q CONNECTICUT e i u v e d r Cat/Del u Kensico t c UV Facility Reservoir all) y H Cit m ro (f Croton Water White es il Filtration Plant Plains M 25 Hillview Jerome Park Reservoir New York City's Reservoir Water Supply System City Tunnel No. 1 Long Island Sound Bronx Catskill/Delaware Watershed Area City Tunnel No. 2 City Tunnel No. 3 Croton Watershed Area Manhattan NASSAU City Tunnel No. 3 (Stage 2) Rivers and Reservoirs Queens/Brooklyn Leg COUNTY Silver Lake Tanks Catskill Aqueduct and Tunnels Queens Groundwater Croton Aqueduct Area Brooklyn Delaware Aqueduct and Tunnels Richmond Tunnel County Borders Staten Island Siphon State Borders Staten Island New York Bay Atlantic Ocean 3 NEW YORK CITY’S WATER SUPPLY SYSTEM New York City’s water supply system provides more than 1 billion gallons of safe drinking water every day to more than 8.4 million residents of New York City; 1 million people living in the counties of Westchester, Putnam, Orange, and Ulster; and more than 60 million tourists and commuters who visit the five boroughs throughout the year. In all, the system provides high-quality drinking water to nearly half the population of New York State. New York City gets its drinking water from 19 reservoirs and three controlled lakes spread across a nearly 2,000-square-mile watershed. The watershed is located upstate in portions of the Hudson Valley and Catskill Mountains that are as far as 125 miles north of the city. New York City’s water supply system is comprised of two primary water supplies called the Catskill/ Delaware and Croton. The city also has a permit to operate a groundwater supply in Southeast Queens, although water from that system has not been delivered to customers in many years. DEP employs more than 6,000 dedicated scientists, engineers, and other professionals who protect, operate, and maintain the water supply system— considered by many to be an engineering marvel. In 2019, New York City received a blend of drinking water from the Catskill/Delaware and Croton supplies. The Catskill/Delaware provided approximately 93 percent of the water, and approximately 7 percent was supplied by Croton. Neversink Reservoir 4 TREATING OUR DRINKING WATER CATSKILL/DELAWARE SUPPLY Due to the very high quality of our Catskill/Delaware supply, New York City is one of only five large cities in the country with a surface drinking water supply that does not utilize filtration as a form of treatment. The Catskill/Delaware supply operates under a filtration waiver, referred to as the “Filtration Avoidance Determination” (FAD). The water from this supply is treated using two forms of disinfection to reduce microbial risk. Water is disinfected with chlorine, a common disinfectant added to kill germs and stop bacteria from growing on pipes. Water is also treated with ultraviolet (UV) light at the Catskill/Delaware Ultraviolet Light Disinfection Facility. The facility, located in Westchester County, is the largest of its kind in the world and is designed to disinfect more than 2 billion gallons of water per day. At the UV disinfection facility, exposure to UV light inactivates potentially harmful microorganisms without changing the water. DEP also adds food grade phosphoric acid, sodium hydroxide, and fluoride to the water before sending it into distribution. Phosphoric acid creates a protective film on pipes to reduce the release of metals, such as lead, from service lines and household plumbing. Sodium hydroxide is added to raise the pH and reduce corrosion of household plumbing. Fluoride is added to improve dental protection, and is effective in preventing cavities at a federally-approved level of 0.7 mg/L. During 2019, only 0.6 percent of the water produced by Catskill/Delaware supply was not fluoridated. DEP’s Distribution Water Quality Laboratory in Queens, NY where DEP scientists analyze thousands of water samples from across the five boroughs seven days a week, 365 days a year. In 2019, New York City’s drinking water met or exceeded all federal and state drinking water standards. 5 CROTON SUPPLY The Croton supply is treated by the Croton Water Filtration Plant, located underground in the Bronx. The plant has the ability to treat up to 290 million gallons of drinking water each day, which helps to ensure a large enough supply of water for the city to withstand droughts. It also allows DEP to periodically shut down other parts of the water supply for repairs and inspections, and increases the flexibility of the City to respond to the evolving effects of climate change. Water undergoes several forms of treatment as it passes through the filtration plant. The process includes coagulation, dissolved air flotation, filtration, and disinfection. During coagulation, chemicals are added to untreated water, causing any particulates to bunch together and become larger particles called floc. Injected air bubbles float the floc to the top where it is skimmed off during the process called dissolved air flotation. Finally, during filtration, the water flows through a bed of anthracite and sand to remove any remaining particles. Just like the Catskill/Delaware supply, Croton water is disinfected with chlorine and UV light to protect against potentially-harmful microorganisms. In addition, Croton water is treated with food grade phosphoric acid, sodium hydroxide, and fluoride. During 2019, 0.01 percent of the water produced by the Croton Water Filtration Plant was not fluoridated. The Croton Water Filtration Plant first began operating in May 2015. In 2019, it was in operation from January 1 to March 20, April 29 to June 3, and October 16 to December 23. 6 TESTING FOR QUALITY DRINKING WATER SAMPLING AND MONITORING DEP monitors the water in the distribution system, upstate reservoirs and feeder streams, and wells that are sources for New York City’s drinking water supply. We continuously sample, and conduct analyses for numerous water quality parameters, including microbiological, chemical, and physical measures, throughout the watershed and as the water enters the distribution system. DEP also regularly tests water quality at nearly 1,000 water quality sampling stations throughout New York City. In 2019, DEP performed approximately 456,500 analyses on 36,300 samples from the distribution system, meeting all state and federal monitoring requirements. These data are summarized in tables starting on page 14. DEP also performed approximately 262,500 analyses on 15,000 samples from the reservoirs and their watersheds. A growing network of robotic monitoring stations provided another 2 million water quality measurements last year, allowing DEP to optimize its operation of the reservoirs, support watershed protection efforts, and study water quality trends.