Newsletter Sign-up Printer Friendly Format Translate This Page Text Size Small Medium Large


May 23, 2003

Contact: Ian Michaels (718) 595-6600

DEP White Paper Explains “Why New York City Needs A Filtered Croton Supply”

Commissioner Christopher O. Ward of the New York City Department of Environmental Protection (DEP) announced today that the agency has issued a white paper explaining the reasoning for why the City needs to filter the water from its Croton water system. The 18-page report, entitled “Why New York City Needs a Filtered Croton Supply,” details issues facing the City’s oldest water system and steps the DEP is taking to address them.

“All data clearly show that filtration in conjunction with a strong watershed protection program is the most effective way to protect the public and increase the reliability of the water supply,” said Commissioner Ward. “"New York City intends to continue, and even enhance, its ongoing program to safeguard the Croton watershed from pollution and development. Filtration will alleviate some real concerns about the quality of Croton water and will help ensure that all areas of the City receive the high quality drinking water that New York is famous for around the world.”

The Croton water system consists of 12 reservoirs and three controlled lakes located in Westchester, Putnam and Dutchess Counties. The smallest of the City’s three reservoir systems, Croton ordinarily provides around 10 percent of the City’s water, though in times of drought or maintenance shutdowns it provides up to 30 percent of the City’s daily needs. Only certain parts of Manhattan and the Bronx receive Croton water.

The 400-square-mile Croton watershed is more densely populated and has more development than the City’s 1600-square-mile Catskill/Delaware watershed, leading the water quality to be lower than Catskill/Delaware water. While the City has received a waiver from the federal Safe Drinking Water Act’s filtration requirements for the Catskill/Delaware watershed, it did not apply for a waiver for the Croton system, preferring instead to build a new filtration plant for Croton.

Among the reasons the white paper cites for needing a filtered Croton supply are:

  • Filtration of the Croton supply will significantly enhance the reliability of the Croton system in meeting downstate water needs in the 21st century. Though the Croton system is sometimes needed to supplement water from the City’s other two water systems (Catskill and Delaware), water conditions in Croton occasionally require that the Croton system be taken out of service completely. These shutdowns often take place in the summer and fall, during peak periods of water demand.

  • Filtration will effectively address the Croton’s chronic problems such as taste, color and odor, will remove midge larva and will enhance public comfort with the adequacy of the Croton water supply. Although Croton System water has continued to meet federal and State health-related water quality standards, during certain times of the year Croton water is affected by seasonal problems that cause aesthetic concerns related to color, odor and taste.

  • Filtration of the Croton System, by removing algae and other organic materials, will reduce the formation of disinfection by-products in the Croton water supply. Disinfection by-products are contaminants that form in water when disinfectants such as chlorine, which are added to kill microbial contaminants, combine with organic material that may be present in the water. While Croton water met the past disinfection by-product rule, it is not expected to meet new federal standards to be issued by the EPA.

  • Filtration of the Croton system will significantly reduce the potential threats posed by microbial contaminants, and help assure high water quality from the Croton system for decades to come. Widespread development throughout the Croton watershed has made Croton System reservoirs more susceptible to microbial contamination. Microorganisms can cause various gastrointestinal disorders and can be potentially life threatening for immunocompromised individuals, for the elderly and for children.

  • Filtration of the Croton System will insure that this reservoir system remains in full compliance with the federal Surface Water Treatment Rule. Extensive development throughout much of the Croton watershed has resulted in a system that does not meet the federal Surface Water Treatment Rule requirement that the water supplier of an unfiltered system demonstrate ownership or control of the watershed to safeguard against human activities that may have an adverse impact on source water quality. Approximately 80% of the Croton watershed is suburbanized. Such urbanized development patterns increase peak flows of stormwater runoff, leading to erosion and streambank instabilities and higher concentrations of pollutants, and also raise the risks from accidental spills.

  • Construction of the Croton filtration plant is necessary for New York City to remain in compliance with the federal Safe Drinking Water Act and a federally enforceable Consent Decree. In 1997, the United States and the State of New York brought an action against the City in U. S. District Court, alleging that the City had failed to filter Croton water in violation of the federal Safe Drinking Water Act and the Surface Water Treatment Rule. In 1998, a Consent Decree was signed in which the City agreed to construct a Croton filtration facility by 2006. A supplement to the Consent Decree in 2002 extended the milestones for completion of construction, New York City remains legally obligated to construct this facility.

  • Advancing a filtration plant for the Croton system reservoirs will not mean an end to watershed protection. New York City has committed to spend hundreds of millions of dollars on Croton watershed management programs, including $200 million for wastewater treatment plant upgrades, $20 million to implement a program to protect selected Croton system reservoirs from non-point sources of pollution and $13.5 million for land acquisition in the Croton watershed. The City and State are also continuing to advance important regulatory programs to protect water quality in the Croton system against specific, future activities.

  • Several investigations have indicated that the combination of filtration and a strong watershed protection program is needed for the Croton system. The City has thoroughly evaluated existing conditions throughout the watershed, natural processes within the reservoirs and on surrounding landscape, existing water quality in streams and reservoirs, and various options for watershed management. The results of these efforts have clearly indicated that the appropriate long-term strategy for the Croton System combines filtration and a strong watershed protection program in a multiple barrier approach.


More Information

NYC Department of Environmental Protection
Public Affairs

59-17 Junction Boulevard
19th Floor
Flushing, NY 11373

(718) 595-6600