Groundwater Protection

Groundwater Protection


What programs is the Nassau County Department of Health involved in that help to protect our groundwater resources?

The Department is involved in many programs to prevent subsurface discharges that have the potential to threaten our groundwater resources. They include the Petroleum Bulk Storage program, Toxic and Hazardous Materials Storage Program, Sewer Connection Program and closure of On-Site Sanitary Systems, monitoring inactive hazardous waste sites and the Underground Injection Control program (UIC).

How do these programs work to ensure protection of groundwater?

The Petroleum Bulk Storage and Toxic & Hazardous Material Storage programs help assure that petroleum and chemical products are properly stored and that any accidental leakage is contained before it can contaminate soil or our groundwater resources.

 The goal of the Sewer Connection program is to connect industrial and commercial facilities to the public sewers where available. Involved with the connection of these facilities to sewers is the proper sampling and closure of existing on-site sanitary systems.

The Department also works with the New York State Department of Environmental Conservation (NYSDEC) and the New York State Department of Health (NYSDOH) during the investigation and remediation of Inactive Hazardous Waste Disposal Sites in Nassau County.

 The UIC program primarily focuses on subsurface drainage structures such as floor drains, drywells, and on-site sanitary disposal systems at commercial facilities, which include dry cleaners, automotive repair facilities, and other industrial facilities that store and use toxic and/or hazardous materials. The United States Environmental Protection Agency (USEPA) Region II Groundwater Compliance Section administers the program and the Department refers sites to EPA that may require investigation. 

What happens when ground water contamination is discovered?

This Department will refer situations where groundwater contamination is found to the appropriate regulatory agency, USEPA or NYSDEC. The facility operator or the property owners (Potentially Responsible Parties or PRP's) are then obligated to enter into legally binding agreements to investigate and clean up contamination. When the PRP's either refuse or are financially unable to perform these activities, the USEPA or NYSDEC may perform the work under the State Spill Compensation Fund or Federal Superfund Program. This Department, in cooperation with the New York State Department of Health, assists the USEPA and the NYSDEC by providing comments and recommendations regarding soil and groundwater investigations and remedial actions.

Sewer Connections & Closures

All facilities located in sewered areas must be connected to public sewers and all existing on-site sanitary systems, which could include cesspools, leaching pools, tile fields and septic tanks, within these areas must be properly abandoned according to the Nassau County Department of Public Works and Nassau County Department of Health guidelines. 

For verification that a property is connected to the Public Sewer System, please contact Nassau County Department of Public Works at 516-571-6841. For the list of local public sewer authorities and their contact information, please click here . For other inquiries, contact Department of Health at 516-227-9692.

Special Groundwater Protection Areas (Article X)


The United States Environmental Protection Agency (EPA) has designated Nassau County groundwaters as sole-source aquifers. The New York State Department of Environmental Conservation (NYSDEC) has designated the best usage of all groundwaters in Nassau County as a source of potable water supply. Several areas within Nassau County have been identified which are relatively underdeveloped and recharge high quality water to the underlying groundwater aquifers which are the prime source of present and future drinking water for county residents. The areas have been designated Special Groundwater Protection Areas (SGPAs).

It is the responsibility of the Nassau County Department of Health to control the amount and types of wastewater being discharged to these aquifers from SGPAs in order to preserve the quality of these aquifers and thereby allow for their continued availability as sources of high quality drinking water. 

Click here to view a map of SGPAs in Nassau County

Does the SGPA limit what I can build on a particular site?

Yes, residential development is limited to one home per 40,000 square feet. Commercial development is limited in that the average daily design rate of sewage per square foot of net area may be no more than 0.00375 gallons.

 How do I know if my proposed development will meet the guidelines of Article X?

Your proposal will have to be submitted to the Department of Health for a review and approval.

 How can I obtain more information?

For more information you may call the Department at (516) 227-9672.


S.E.P.T.I.C. Program

Nassau County Department of Consumer Affairs has initiated a septic system replacement program for residents and small businesses -- Septic Environmental Program to Improve Cleanliness (SEPTIC). The SEPTIC program will provide grant funding to eligible recipients to replace a conventional or failing septic system with an innovative and alternative onsite wastewater treatment system. Nassau County is offering grants up to $20,000 for homeowners or small businesses to install state-of-the-art nitrogen reducing septic systems.

This grant is available to residents in non-sewered areas of Nassau County.

For more information or to apply, please visit

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