Stormwater Management Program

In an effort to preserve Long Island’s coastal heritage and natural resources, Nassau County has taken the initiative to create an intermunicipal Nassau County Storm Water Management Program (NCSWMP). This program will depend on the participation of every municipality in the county to work with the New York State Department of Environmental Conservation to manage our storm water and reduce the toxic runoff that affects our lakes, streams and coastal waterways. 

View the NCSWMP Plan.

Quality Standards
Roughly 40% of our nation’s surface waters do not meet water quality standards, and are contaminated by pathogens, excess nutrients and chemical pollutants. The health of these surface waters is vital to human health, wildlife, and to our regional economies. Yet every day, stormwater runs into these important water bodies after being contaminated by surface wastes, chemicals, and excess sediment.

View the Drainage Requirements.

Purposes of Stormwater Management
Stormwater discharges directly into our open waters or to our groundwater system. Unlike water, which is used in many of our homes, stormwater is not collected in a sewer system and passed through a water treatment plant before being discharged. Instead, it is collected in almost 1,000 groundwater recharge basins or directed to the south shore bays or Long Island Sound through 3,720 storm water outfalls or almost 60 miles of open stream corridors.
More on this can be viewed in the Runoff Impact Analysis.

This means that contaminants that are picked up by storm water after it falls on our county’s roads, parks, homes, and parking lots flow directly into the groundwater system that we use for our drinking water, or into the sensitive open waters surrounding our island. These pollutants include nutrients, silt / sediment, pathogens, oil / grease, metals, debris, and litter. The New York State Department of Environmental Conservation and Nassau County are working together to reduce six pollutants of concern:

  • Nitrogen
  • Oxygen Demand
  • Pathogens
  • Phosphorus
  • Polychlorinated Biphenyls
  • Silt and Sediment

What Is the County’s Role?
The NCSWMP is a comprehensive program to reduce the levels of contaminants in Nassau County’s storm water runoff and educate the public about their impacts on storm water. Storm water systems are the responsibility of the County and its 67 Towns, Villages, and Cities. As the largest municipality, Nassau County has taken the lead in coordinating the NCSWMP and acting as a clearinghouse of information for concerned parties. The Nassau County Department of Public Works Water Engineering Unit is in charge of implementing the plan, including water testing, education, and pollution prevention measures. The six elements of the NCSWMP are:

Private citizens can do a lot to prevent pollution from entering our storm systems and waterways. Click here to find out what you can do to improve our water’s health!

2014 Annual Report
The 2014 Annual Draft Report for the Nassau County Storm Water Management Program is hereby presented on this web site in order to solicit comments from the general public with regard to our program. Please submit all comments to the following email address by May 31, 2014, The report can be found below under Documents.

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