Innovative/Alternative Onsite Wastewater Treatment Systems — commonly called I/A systems or I/A OWTS — represent a significant upgrade over traditional cesspools and conventional septic systems. Suffolk County actively promotes I/A technology because of its demonstrated ability to reduce nitrogen in treated effluent before it reaches groundwater and surface water.
Why Nitrogen Reduction Matters for Suffolk County
Long Island's groundwater and coastal waters have experienced elevated nitrogen levels tied in part to onsite wastewater systems. Excess nitrogen contributes to harmful algal blooms, reduced water quality, and environmental stress in bays, harbors, and estuaries that define the character of Suffolk County. Replacing older cesspools with nitrogen-reducing I/A systems is one of the county's primary strategies for addressing this problem.
How I/A Systems Work
While conventional cesspools and septic systems provide only primary treatment — physical separation of solids — I/A systems add a secondary treatment stage. This typically involves biological processes, aeration, or filtration that break down nitrogen compounds before effluent disperses into the ground. The result is substantially lower nitrogen concentrations in the treated water.
Several manufacturer technologies are approved for use in New York State. Your contractor and the Suffolk County Health Department will help determine which system is appropriate for your specific property, lot size, setback requirements, and soil conditions.
The Grant Connection
Suffolk County's Septic Improvement Program requires installation of an approved I/A system. Eligible homeowners may qualify for:
- Suffolk County SIP: Up to $20,000 depending on qualification
- New York State program: Up to $25,000 depending on qualification
- Combined potential: Up to $45,000 — subject to eligibility, program terms, and available funding
See our complete Septic Grant Guide for current program details, eligibility information, and application guidance.
Installation Requirements
I/A system installations require approval through the Suffolk County Department of Health Services before work begins. An approved, licensed contractor must perform the installation. The county inspects the work, and the homeowner is typically responsible for an ongoing maintenance contract with a certified service provider — I/A systems have moving parts and monitoring requirements that conventional systems do not.
Ongoing Maintenance
Most I/A systems require an annual or semi-annual service contract. The maintenance provider will inspect system components, check electrical systems (many I/A systems use aeration equipment), and confirm the system is performing as designed. This ongoing maintenance obligation is a condition of both the installation permit and the grant program.
Is an I/A System Right for Your Property?
I/A systems are not universally suitable for every lot. Minimum setback requirements, soil conditions, lot size, and proximity to water bodies all affect what type of system can be installed and where. A licensed contractor and the Suffolk County Health Department can evaluate your specific property and advise on what is possible.
Frequently Asked Questions
Can I get the grant without installing an I/A system?
No. The Suffolk County Septic Improvement Program specifically requires installation of an approved I/A OWTS. The grant is not available for conventional septic system replacements.
How long does I/A system installation take?
The installation itself is typically completed in a day or two once permits are in place. However, the permitting process, system design, and grant application process can take considerably longer. Starting the process early is advisable.
What happens if the I/A system malfunctions?
Most I/A systems include alarm systems that alert homeowners to operational issues. Your maintenance contractor is responsible for addressing system malfunctions. This is why the maintenance contract requirement exists.