New York City


New York City has one of the few sources of natural, unfiltered water in the U.S. It is the largest water system in the country operating under an approved filtration avoidance waiver. The abundant reserve of forest, as well as soil with adequate carbon levels, is essential to the Catskill/Delaware watershed’s excellent conditions for natural filtration.

The natural filtering abilities of New York’s ecosystems, wetlands and waterways were being threatened by development, runoff from agricultural lands and impervious surfaces, and discharges from wastewater treatment plants at a time that the city faced the potential major investment in a new treatment facility.

Water System and Watershed

The Catskill/Delaware, or Cat/Del system, drinking water supply system consists of four Delaware reservoir watersheds (Cannonsville, Pepacton, Neversink and Rondout) and two Catskill reservoir watersheds (Askokan and Schoharie) west of the Hudson River. Due to the Delaware aqueduct connection with Branch Reservoir and Cat/Del system discharge into Kensico Reservoir, the system also includes West Branch-Boyd’s Corner Reservoir and Kensico Reservoir watersheds, both east of the Hudson River. Ninety percent of the City’s water is from the 1,600 sq. mile area Catskill/Delaware Watershed. The upper watershed consists primarily rural area of farms, forests and small towns with growing number of suburban developments and vacation homes.

Amount of water

1.3 billion gallons per day to 9 million people in New York City.

Cost savings

$6-$8 billion for construction of new filtration facility
$200-$300 million operation and maintenance costs

Lead Agency(ies)

New York City, Department of Environmental Protection

Agreement Vehicle

A Memorandum of Understanding (MOU) signed in 1997 by New York City, communities of Catskill/Delaware watershed, U.S. EPA, state of New York, and certain environmental organizations in exchange for a filtration avoidance waiver from EPA. EPA reissued New York City a Filtration Avoidance Determination (FAD) in November 2002.

Program Implemented

New York City chose to implement a comprehensive watershed protection program to preserve and restore natural filtration services as a more cost effective means of maintaining water quality than water treatment.

1997 Watershed MOU/FAD

Watershed management measures included land acquisition and comprehensive planning, water quality monitoring and disease surveillance, and upgrading wastewater treatment plants.

MOU stipulated that New York City solicit purchase of 355,000 acres of land in the watershed between 1997 and 2007, coupled with $250 million commitment from the city. Conservation easements funded through federal, state, and city strategies including USDA Conservation Reserve Enhancement Program (CREP). Land was to be purchased from willing sellers and full market price. Wastewater treatment plant upgrades at cost of $70 million were funded by city of New York.

City also shared cost of implementing agricultural, forest and stream BMPs including buffers and setbacks, soil-conserving tilling and grazing practices, stream-bank fencing, and erosion-prevention forestry practices. Watershed Agricultural Council (WAC) assisted agricultural and forestry communities with adopting management techniques to protect water quality and enhance economic viability. Conservation easements provided landowners with annual payments in exchange for maintaining the land in a natural state.

2002 FAD
The renewed FAD continues protection and remediation program called for in 1997 FAD with city providing necessary funding to meet milestones, as well as significant expansion of a number of programs. Cost to New York City of watershed protection programs is approximately $1.3 billion.

Status of programs

  • Land Acquisition Program. This is the foundation of the watershed protection program. Overarching goal is to ensure that undeveloped, environmentally-sensitive watershed lands remain protects and the watershed continues to be a source of high-quality drinking waters to the City and upstate counties. EPA’s continuance of filtration avoidance rests largely on success of this program.
  • City continues to solicit for acquisition of land, either to acquire outright or to acquire conservation easements which restrict development. Between 1997 and 2003, City obtained or had under contract over 52,000 acres at a cost of $131 million. Over 70% of the acreage obtained is in high priority areas, including 1,200 acres of wetlands. City is also working with local land trusts to increase solicitation. City is more than 1/3 of the way through a 15-year program.
  • Wastewater Treatment Plant Upgrade. City is upgrading all City- and non-City owned wastewater treatment plans that discharge into surface water in the watershed to tertiary treatment technology. Cost is over $200 million. Over 90% of wastewater flow is subject to advance tertiary treatment. All plants are expected to be operational by end of 2004.
  • Stream management program. To address pervasive stream degradation that has contributed to erosion and loss of riparian buffers, FAD continues milestones for 10 large restoration projects through 2007 and completion of 9 stream management plans.
  • Agricultural program. Over 95% of large farms in the watershed are enrolled in this voluntary program. More than 2,500 actions have been implemented using BMPs at a cost of $18.6 million. 2002 FAD expanded this program to include small farms.
  • Other programs include: new wastewater infrastructure program, community wastewater management program, septic program, Catskill Turbidity Control program, UV disinfection facility, as well as more emphasis on enforcement and more comprehensive monitoring and program analysis.


  • Significant cost savings over the build and operation of a filtration plant.
  • Wastewater treatment upgrades expected to result in 90 percent of wastewater flow being micro-filtered and safer drinking water benefiting both rural and urban residents.
  • Preservation of open space and rural character of Catskill/Delaware watershed, increasing opportunities for agriculture and forest-based businesses.
  • Ecosystem services benefits realized including steps towards market development of previously unrecognized economic opportunities.
  • Protection of other valuable services such as flood control, storage of carbon by plants.


David Warne
Chief of Staff
Bureau of Water Supply
Department of Environmental Protection
New York City
(914) 742-2099


Appleton, A. 2002. How New York City Used an Ecosystems Services Strategy Carried Out Through an Urban-Rural Partnership to Preserve the Pristine Quality of its Drinking Water and Save Billions of Dollars. A Paper for Forest Trends, Tokyo, November 2002. Accessed at:

Murphy. S., J.W. Tone, and P. Schwartzberg. Land Acquisition for Water Quality Protection: New York City and the Catskills Watershed System. in Integrated Watershed Management - A New Paradigm for Water Management? Robert C. Ward, ed. Water Resources Update. Universities Council on Water Resources (100) Spring1995. 60-62. Accessed at:

New York City. 2001. New York City’s 2001 Watershed Protection Program Summary, Assessment and Long-term Plan. New York City Department of Environmental Protection, Bureau of Water Supply. Accessed at:

New York City. 2002. New York City 2002 Drinking Water Supply and Quality Report. New York City Department of Environmental Quality. Accessed at:

New York City. 2004. Filtration Avoidance Annual Report for the period January 1 through December 31, 2003. New York City Department of Environmental Protection, Bureau of Water Supply. Accessed at:

Nickens, E. 1998. A watershed paradox – New York City’s water quality protection efforts. American Forests. Winter 1998.

U.S. EPA. 1996. Watershed Progress: New York City Watershed Agreement. Dec. 1996, EPA840-F-96-005.

U.S. EPA. 1999. Protecting Sources of Drinking Water: Selected Cases in Watershed Management. EPA 816-R098-019.

U.S. EPA. 2000. Assessing New York City’s Watershed Protection Program. The 1997 Filtration Avoidance Determination Mid-Course Review for the Catskill/Delaware Water Supply Watershed. U.S. EPA Region 2. May 2000.

Web Sites

New York City’s Water Supply System. Watershed Agreement Overview.

Map (Catskill/Delaware Water Supply System) (Catskill/Delaware Watershed)