Suffolk County septic grant (2026): up to $45,000, explained

Not a government website. We aren't affiliated with Suffolk County, Nassau County, any town, or New York State, and we can't approve or speed up a grant. Grants go through the official programs, Suffolk SIP (Reclaim Our Water) and Nassau SEPTIC, and the installer you hire handles the grant process with you.

The grant stack

Who qualifies (and the traps)

• You must apply for, and be issued, the grant before the I/A system is installed.
• The house must be on a cesspool or septic system, not connected to a sewer and not inside a proposed sewer district.
• The old system must be abandoned and replaced with an approved I/A (nitrogen-reducing) system.
• New construction on a vacant lot isn't eligible.
• The deed must be recorded with the Suffolk County Clerk, property taxes must be current (no liens or foreclosure), and the house needs a valid Certificate of Occupancy.
• You must use an installer on the County's SIP-Approved Installer List. The County pays that installer directly, and for a straight replacement the County says your installer applies on your behalf.
• Applications with a documented system failure are prioritized ahead of all others.

The three most common ways people lose the grant: starting work before the grant is issued, hiring an installer who isn't on the SIP-approved list, and finding out after paying for a design that the street is in a proposed sewer district. Check all three first.

How the process works, step by step

You don't have to run this yourself. SIP-approved installers do grant jobs every day and handle the paperwork with you; you sign what the County needs signed. Here's what happens behind the scenes, from the County's 2026 process overview:

1. ApplicationThe online application at suffolkcountyny.gov/septicgrants needs your town-issued tax bill and, if your system has failed, proof (photos, pumping receipts). For a straight replacement, the County says your selected SIP-approved installer applies on your behalf.
2. Scoring and rankingComplete applications are scored. A documented failure and a priority-area location move you up. The County says it now responds in about a week.
3. Award and 30-day signatureYou're emailed the County SIP and State SSRP grant agreement. Sign and return it within 30 days.
4. Hire a design professionalYou hire (and pay) an engineer or design professional, who files the design with the County Office of Wastewater Management and flags any town, village or state permits.
5. Permit to ConstructThe County issues the Permit to Construct for your I/A system.
6. Pick an approved installerChoose an installer from the SIP-Approved list. They price the approved plans, you sign Assignment of Payment forms, and the County issues a Grant Eligibility Memo.
7. Install and inspectionWork starts after the installer gets the OK to Proceed. County inspectors check the install and witness start-up, and the old system is abandoned.
8. Paperwork and paymentAs-built plans, abandonment certification, an operation and maintenance agreement and registration are filed. The County then pays the grant to your installer.

Program contact: Your SIP-approved installer handles the application with you (suffolkcountyny.gov/septicgrants). County questions: SepticGrants@SuffolkCountyNY.gov or (631) 852-5811.

Town programs on top of the County and State grants

Town of Southampton I/A OWTS Rebate (Community Preservation Fund)

Up to $20,000 base, plus up to $5,000 more for low-to-moderate income (max $25,000). Properties in a Southampton Water Quality Improvement Priority Area.

• The property must be in a Priority Area (check it with the Town's GIS tool). A collapsing system outside one may still qualify, so call.
• Must replace an existing system. New construction on vacant land isn't eligible.
• Covers costs tied to the upgrade, including removal, design, labor and materials, a 3-year maintenance contract and restoration. It doesn't cover costs already paid by County or State grants.
• The Town expanded its priority-area maps to match County standards on March 10, 2026, so more homes qualify.
• Rebates are paid about 60–90 days after the final paperwork, which is due within one year of County final approval.

Town of East Hampton Septic Incentive Program

Up to $20,000 in the Water Protection District, up to $15,000 elsewhere in town. East Hampton Town property owners.

• Start with the Town's eligibility verification form (Form 1).
• Covers approved costs of replacing a septic system with a low-nitrogen system.

The calculator uses $20,000 (Water Protection District). Outside it, the cap is $15,000.

Town of Shelter Island I/A Rebate (Community Preservation Fund)

$12,000 base, plus up to $5,000 for a pressurized shallow drainfield and up to $4,000 if a well must move. Shelter Island property owners making a voluntary upgrade.

• Apply to the County and State programs first.
• For voluntary upgrades only, not when an upgrade is required (new construction or alterations that increase flow).
• The Water Quality Improvement Advisory Board reviews applications and recommends funding to the Town Board.

Figures come from local reporting. Confirm with the Town's WQI page before you budget.

Other Suffolk towns (including Brookhaven, Islip, Huntington, Smithtown, Riverhead and Southold) didn't have a separate town rebate when we checked. See your town page.

After the install: maintenance

The grant covers the first 3 years of maintenance. After that you need an annual contract with a licensed I/A maintenance provider (about $300 a year is a common estimate). Homes in the Peconic Estuary contributing area (much of Riverhead, Southold, Southampton, East Hampton and Shelter Island) can get up to $500 a year toward a renewed i/a maintenance contract (announced; check that it's open before counting on it).

Taxes

In 2020 the IRS said Suffolk's septic grants were taxable, and the County sent out 1099s. In November 2022 the IRS reversed that in Announcement 2022-26: County SIP payments aren't included in homeowners' gross income, and the County has no 1099 reporting duty for them. The announcement covers the County SIP payments; ask a tax professional about the State and town portions.