Stormwater Management Program

Nassau SWCD Video 

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 July 2024 NCSWMP (pdf) here
View the 2019 SWMP here

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 (PDF).

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 (PDF).

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: