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October 15, 2008

Contact: 311

Important Information for Consumers of the New York City Croton Water Supply System

Protecting the Water Supply

Federal law and State regulations require that all New York State surface drinking water supply systems filter the water delivered to consumers, unless the system can meet strict conditions for “filtration avoidance,” including protection of the related watershed from where the surface water originates. New York City obtains virtually all of its drinking water from three surface water systems originating in upstate watersheds. The systems are known as the Croton, Catskill and Delaware systems. Since the early 1990s, the City has pursued a comprehensive watershed protection strategy, for its three water systems, to protect the quality of its drinking water at the source. The City’s program includes, among other things, enforcement of updated watershed rules and regulations, the acquisition of sensitive watershed lands, and the funding of economic and environmental partnerships with watershed counties, towns and villages to support local efforts aimed at maintaining or enhancing water quality.

Croton Filtration Plant
Construction of Croton Filtration Plant under Mosholu Golf Course.

In July of 2007, the United States Environmental Protection Agency (USEPA) renewed its previous decision and issued a 10-year Filtration Avoidance Determination (FAD) for the City’s two largest systems, the Catskill and the Delaware. Under this FAD, the City is not required to filter these two systems. However, the City, the State and USEPA have determined that the Croton system (the City’s oldest, supplying about 10% of the City’s daily drinking water, and up to 30% in times of drought) should be filtered.

The Croton System
(Public Water System ID# NY7003666)

Croton system water is not currently filtered, which constitutes a treatment technique violation under federal and State drinking water regulations. Due to its unique history and geography (very different from both the Catskill and Delaware systems), the Croton system also experiences seasonal water quality problems associated with elevated color levels, resulting from naturally occurring minerals and organic matter present in the water. Although this condition is aesthetic and not health-related, it may require the City to discontinue use of Croton system water while color levels remain elevated, or to blend Croton system water with Catskill system water.


The City’s goal is to ensure that Croton system water is at all times protected against microbiological contamination, is aesthetically pleasing, and meets all drinking water quality standards. The City is, therefore, proceeding with the construction of a filtration plant for Croton system water, pursuant to the terms of a November 1998 federal court Consent Decree, entered into with the United States and the State of New York. The filtration facility is expected to reduce color levels in the Croton system water, reduce the risk of microbiological contamination, reduce disinfection by-product levels and ensure compliance with stricter water quality standards.

The Consent Decree, as modified in May 2002, required the City to evaluate and choose between three potential sites for the filtration plant: two in the Bronx, at the Mosholu Golf Course within Van Cortlandt Park, or along the Harlem River in the vicinity of Fordham Road, and one at Eastview in Westchester County. The City sought State legislation authorizing the alienation of the Mosholu Golf Course site for the purpose of constructing, operating and maintaining a Croton filtration plant. In July 2003, after passage by the State Legislature, the Governor approved such legislation and signed it into law. A Final Supplemental Environmental Impact Statement comparing the three sites was released on June 30, 2004 and it identified the Mosholu Golf Course Site as the preferred site for the facility. On September 28, 2004, the City issued a notice to proceed to begin the first phase of construction of the filtration plant. On August 23, 2006 and on August 21, 2007 the City issued notices to proceed with the second and third phases of construction. Work continues to make steady progress in 2008.

The Law

Until the City begins to filter Croton water, the New York City Department of Environmental Protection is required to send to customers of the Croton Water Supply, the following information quarterly:

The United States Environmental Protection Agency (EPA) sets drinking water standards and has determined that the presence of microbiological contaminants is a health concern at certain levels of exposure. If water is inadequately treated, microbiological contaminants in that water may cause disease. Disease symptoms may include diarrhea, cramps, nausea, and possibly jaundice, and any associated headaches and fatigue. These symptoms, however, are not just associated with disease-causing organisms in water, but also may be caused by a number of factors other than your drinking water. EPA has set enforceable requirements for treating drinking water to reduce the risk of these adverse health effects. Treatment such as filtering and disinfecting the water removes or destroys microbiological contaminants. Drinking water which is treated to meet EPA requirements is associated with little to none of this risk and should be considered safe.

For More Information

If you have questions about the New York City water supply system or filtration, please write:

New York City Department of Environmental Protection
Bureau of Public Affairs
59-17 Junction Boulevard, Flushing, New York 11373

You can also contact DEP by calling 311, the City’s Non-Emergency Communication Center or visit DEP’s Web site.

More Information

NYC Department of Environmental Protection
Public Affairs

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

(718) 595-6600