est water in the world ! the b has YC take our word for it . N n’t just t do Bu New York City Vincent Sapienza, P.E. Commissioner Drinking Water SupplyBill de Blasio and Quality Report - 2020 Mayor 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 Vincent Sapienza, P.E. Commissioner Dear Friends: This past year has presented our agency, our city, and our nation with historic challenges. The work we do at the Department of Environmental Protection (DEP) has never been more vital to protecting the health of New Yorkers. Despite the challenges presented by the COVID-19 global pandemic, we have remained focused and disciplined in our commitment to being a world-class water utility and building a sustainable future for all New Yorkers. At DEP, we are no strangers to confronting situations that require quick thinking and innovative solutions. Through all the challenges we faced in 2020, I am proud to report that each day we continued to deliver one billion gallons of the best tap water in the world to more than 9.3 million New Yorkers. In this report, you will see that New York City’s drinking water continued to meet or surpass every national and state standard for quality. These data are based on 43,600 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 530,000 times by scientists working in our four water quality laboratories. Robotic monitoring stations on our reservoirs provided another 2.7 million tests to ensure DEP was sending the best-quality water to New York City at all times. I want to especially thank the many DEP employees who went above and beyond in 2020, putting their commitment to public service before themselves, and truly embodying DEP’s core values. And, as we embark on a new decade, I also want to thank each of 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 Throughout the COVID-19 pandemic, DEP’s 6,000 dedicated scientists, engineers, and other professionals continued to protect, operate, and maintain New York City’s water supply system, delivering high-quality drinking water to millions of New Yorkers around the clock, without interruption NEW YORK CITY’S WATER SUPPLY SYSTEM New York City’s water supply system provides more than one billion gallons of safe drinking water every day to more than 8.3 million residents of New York City and one million people living in the counties of Westchester, Putnam, Orange, and Ulster. In 2020, we delivered 104 million gallons per day to 74 communities and institutions outside NYC. In all, this system provides nearly half the population of New York State with high-quality drinking water. 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 surface 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. In 2020, New York City received a blend of drinking water from the Catskill/Delaware and Croton supplies. The Catskill/Delaware provided approximately 96 percent of the water, and approximately 4 percent was supplied by Croton. An estimated 10 percent of the water supply was lost due to distribution system leakage. 2020 DRINKING WATER SUPPLY AND QUALITY REPORT 3 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), and 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, and then with ultraviolet (UV) light at the Catskill/Delaware UV Disinfection Facility. The facility, located in Westchester County, is the largest of its kind in the world and is designed to disinfect more than two 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 is added because it creates a protective film on pipes that reduces the release of metals, such as lead, from service lines and household plumbing. Sodium hydroxide is added to raise the pH which reduces 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 2020, only 0.2 percent of the water produced by Catskill/Delaware supply was not fluoridated. CROTON SUPPLY The Croton supply is filtered 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, periodically shut down other parts of the The New Croton Reservoir Dam water supply, and respond to the potential effects of climate change. The Croton Water Filtration Plant first began operating in May 2015. Once water arrives at the filtration plant it undergoes treatment to remove impurities. The treatment processes include 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. Then injected air bubbles float the floc to the top where it is skimmed off using a process called dissolved air flotation. Finally, the water flows through a filter bed removing any remaining particles. Just like the Catskill/Delaware supply, Croton water is disinfected with chlorine and UV light to protect against potentially-harmful microorganisms, and is treated with food grade phosphoric acid, sodium hydroxide, and fluoride. In 2020, DEP upgraded the material in the filter beds from anthracite to granular activated carbon (GAC) to improve the plant’s performance. Once the change was completed, the plant resumed operations on October 27 to December 31, during which time, only 0.6 percent of the water produced by the plant was not fluoridated. 20202020 DRINKING DRINKING WATER WATER SUPPLY SUPPLY AND AND QUALITY QUALITY REPORT REPORT 4 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 potential 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 2020, DEP performed over 363,200 analyses on 31,300 samples from the distribution system, meeting all state and federal monitoring requirements.