Nassau Septic

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


Nassau County 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.

Nitrogen pollution from cesspools and septic systems has been identified as the largest single cause of degraded water quality on Long Island, contributing to beach closures, restrictions on shellfishing, toxic algae blooms, and massive fish kills. A conventional onsite septic system was never designed to remove nitrogen. The average residential septic system discharges approximately 40 pounds of nitrogen per year.

Tens of thousands of homes and small businesses in Nassau County are currently served by cesspools and septic systems. Reversing degradation of water quality will depend on replacement of existing systems with these new nitrogen reducing technologies. When properly designed, sited, installed, managed, and maintained, these new septic systems provide a cost-effective and environmentally sound alternative to sewers in areas that are outside designated sewer areas. These systems significantly reduce nitrogen, biochemical oxygen demand and total suspended solids, before being discharged below grade to leaching structures.

These nitrogen removing systems can provide greater performance reliability and enhanced treatment that helps to protect public health and the environment.

Nassau’s S.E.P.T.I.C. Program – Eligibility

  • Single family, two family, not-for profit organizations,  and small businesses with an existing sanitary design flow less than or equal to 1,000 gallons per day (GPD) may be eligible for this program.
  • The project must be a replacement of an existing septic system or cesspool with a new nitrogen reducing IA OWTS.  The IA OWTS must have been installed after March 1, 2018 to be eligible for the S.E.P.T.I.C. grant funding.

In addition, participating properties MUST:

  • Have a valid certificate of occupancy or existing use issued by the pertinent city, town or village.
  • Be served by an existing septic system or cesspool and not be connected to a public or private sewer or located within an existing or proposed sewer district.  If the property is located in an existing sewer district but is unable to connect due to site constraints documented by the Sewer District in question, the property may be eligible, provided the applicant meets all other eligibility requirements.
  • Not have any outstanding or open real property tax liens.

Nassau’s S.E.P.T.I.C. Program – Technologies

The following technologies are currently accepted for use as part of the S.E.P.T.I.C. Program:

How do these Technologies Reduce Nitrogen?

The technologies listed above all utilize biological processes to treat wastewater and remove nitrogen. These systems use various methods to provide aerobic bacteria to convert organic nitrogen to nitrite and nitrate and then use an anaerobic (without oxygen) environment to denitrify by stripping the oxygen molecule off the nitrate nitrogen, resulting in the release of gaseous nitrogen into our atmosphere. The nitrogen cycle is one of Earth’s most important biological process, second only to photosynthesis. 

For more information, please contact or 516-364-5861.