Nassau County has initiated a septic system replacement program for residents, small businesses and non profits - 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.  

For more information, please contact us at  or  (516) 364-5861


OR visit our page on the Nassau County website at

Why Nitrogen Reducing Systems?


Nitrogen pollution from cesspools and septic systems has been identified as the largest single cause of degraded water quality 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.

How do they work? 

All five of the Provisionally Accepted Technologies in Nassau County rely on 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 of 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 to only photosynthesis.

Learn More about the Nassau County Septic Program

I/A Septic Systems Accepted for the Program - Browse the Innovative and Alternative Septic Systems available for applicants of the SEPITC Replacement Program, here you will find links to the manufacturer webpage and contact information. 


Frequently Asked Questions - Questions Regarding S.E.P.T.I.C. Grant Program, Clean Water (nitrogen-reducing) Septic Systems and the S.E.P.T.I.C Grant Program Application process.


Industry Resources - For Installers or Designers interested in Participating in the program. Here you will find guidance memos and resources that outline the program rules and limitations. 

Applicants Currently Enrolled

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Nassau S.E.P.T.I.C. Grant Program - Clean Water Septic Vendor Day

The Nassau County Soil and Water Conservation District participated in the Long Island Clean-Water Vendor Day! This event brought awareness to the community about outdated, failing, conventional septic systems. These outdated septic systems are the number one cause of nitrogen pollution in Long Island, leading to harmful algal blooms, thick mats of seaweed, fish kills and the overall decline of the shellfish industry. Switching to new innovative and alternative septic systems can remove more than 70% of the nitrogen pollution from our wastewater!

Vendor Day displayed Nassau County accepted innovative and alternative septic system designs. Attendees had the opportunity to ask questions to expert distributors and representatives from the Nassau S.E.P.T.I.C. program.

Site tours of successfully installed nitrogen-reducing systems!

I/A Septic System Installations

Nassau County SWCD attending the first clean water septic instillation

How to Maintain your Septic System


Making sure your I/A system is properly maintained will save you time and money while also allowing the system to sufficiently reduce the harmful nitrogen from your wastewater.


Most of these tips and tricks found in our Do's and Dont's for your I/A Septic System flyer apply to conventional systems as well, so caring from this system is not too different from what you're used to.


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Do Not Flush "Flushable" Wipes


Maintaining your septic system starts with not flushing products that hurt your system. "Flushable" wipes and baby wipes can cause blockage inside your pipes or system.

Chemical additives marked to unclog drains, break up oil and greese may also contain acids, solvents, hydrogen peroxide or strong caustic agents. Overtime, excessive use of antibacterial products like wipes can kill off the beneficial bacteria that helps the system operate. 


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