Verified as of September 16, 2026. We re-check these pages quarterly.
Every condition below has to be true at the same time. Miss one and the application does not proceed, so it is worth twenty minutes with the list before anyone quotes you anything.
The checklist
- An existing residential home — single-family, two-family, or single-family with one accessory apartment.
- Served by a cesspool or septic system that is being replaced under the grant. The existing system must be abandoned and replaced with the I/A system.
- Not connected to sewers, and not within a proposed sewer area.
- A valid certificate of occupancy for the property.
- A current town-issued property tax bill.
- Taxes current, with no tax liens and not in foreclosure.
- A deed recorded with the Suffolk County Clerk.
- County approval of the I/A project from the Department of Health Services Office of Wastewater Management, before a grant is awarded.
- An installer from the County Approved Installer List. Only vendors on that list may install a grant-funded system.
- Applied for and issued before installation. New construction on a vacant lot is not eligible at all.
The sewer test is the one that catches people
"Not connected to sewers and not within a proposed sewer area" is doing more work than it looks. Suffolk is mostly unsewered, so most homeowners assume it does not apply to them, and most are right — but "proposed" is a real category with real boundaries, and they are not where you would guess from the street.
We checked this against the county's own data rather than a road map. The parcel layer behind the county's eligibility map carries, for every parcel, the county's own eligibility flag, whether it sits in a sewer district, and the lifecycle status of that district. What it shows is worth knowing:
- Being inside an active sewer district is, countywide, the thing that most reliably produces a "Not Eligible" result.
- Being inside a proposed district does not automatically produce one. Across the county, far more parcels inside proposed districts are flagged Eligible than are not.
- The two areas where proposed districts cover the most ground are Mastic Beach, almost entirely inside the proposed Forge River Watershed Sewer District Phases III & IV, and Mastic and Shirley, where about a third of built parcels sit inside that or the proposed treatment plant expansion. Even there, the county's own map returns Eligible for the large majority of built parcels.
So: a proposed sewer project near you is not a verdict, and neither is the absence of one. It is a parcel-level test.
Check your own address
The county publishes an eligibility map that answers this by address, and it is the only answer that counts. Find it from the county's grant page at suffolkcountyny.gov/septicgrants, under "Check Here to See If Your Property is Eligible". If the result is not what you expected, or the property sits on a boundary, call the grants team on 631-852-5811 before you assume anything.
What is not on the list
A few things people expect to be conditions, and are not, at least not in the published conditions:
- There is no stated primary-residence requirement. The condition is an existing residential home with a valid certificate of occupancy. If you have a seasonal house out east, do not rule yourself out without asking.
- There is no stated income cap.
- Sewers being planned for your street eventually is not the same as a proposed sewer area. The county's own view is that it may be 10 to 20 years before a planned sewer arrives, and that many areas of Suffolk will never see one.
We are stating what the county publishes. Where the county has not published a condition, we are not inventing one — but the county decides, and its own disclaimer says the information is subject to change.
If you qualify
Applications with a documented system failure are prioritized before all others, and the published process scores completed applications on documented failure and priority area. Gather the current town tax bill and any evidence of failure — photographs, service receipts — before you start. The form itself takes minutes and the county says it responds in about a week.
Verified as of September 16, 2026. We re-check these pages quarterly. The eligibility conditions were confirmed against Suffolk County's own Septic Improvement Program page and its 2026 homeowner process overview on that date. The sewer-district findings were taken from the parcel layer behind the county's own SIP eligibility map, checked in September 2026. Confirm current availability before counting on a number.
All work is performed by local licensed, permitted Suffolk County-approved installers.