Verified as of September 16, 2026. We re-check these pages quarterly.
If you are taking the grants, this is not optional: only vendors on Suffolk County's Approved Installer List may install a grant-funded I/A system. Hire anyone else and the work may be perfectly good and the grant will not pay for it.
The county publishes the list as a PDF from its grant page at suffolkcountyny.gov/septicgrants. It runs to several dozen companies across the county.
Why the list exists
The county is not buying a system, it is buying a result it has to stand behind for the life of the property. An I/A system is a piece of treatment plant in a residential yard: it has a control panel, an air supply, alarms, and a maintenance obligation that does not end. The county inspects the installation, witnesses start-up, and takes as-built plans afterward. The list is how it keeps that manageable.
It also changes where your leverage is. Because the county pays the installer directly, the installer is being paid by an organization that will be inspecting their work and can remove them from the list. That is a better position for a homeowner than it sounds.
How the money reaches them
- You are issued a grant and e-sign the grant agreement within 30 days.
- Your design professional gets a permit to construct from the Office of Wastewater Management.
- You select an installer from the list and submit their price quote based on the approved permit site plans, and sign assignment of payment forms.
- The county issues a grant eligibility memo based on that quote — this is the number that actually applies to your job.
- The installer gets an "OK to proceed", installs, and the county inspects and witnesses start-up.
- The installer submits certification forms; you submit an operations and maintenance agreement and an I/A registration form from your maintenance provider.
- The county issues payment to the vendor named on the assignment of payment forms.
Note step 3. The quote comes after the permit site plans, not before. A price given before the design exists is not a price, it is an opinion.
What to ask before you choose
- Which technology are you proposing, and why this one for this site? Suffolk approves several. They differ in footprint, in whether they run a blower continuously, and in what they cost to keep going.
- What will the operations and maintenance contract cost once the county's first three years are up? The county's own figure is $300 to $600 a year. Get theirs in writing now, not in year four.
- Does this design need a town or village building permit, or a wetlands permit? On the East End it often does, from the Town Trustees or the state DEC. Your design professional identifies these — ask early, because they take time.
- What will the site look like afterward? The county warns of extensive site disruption during installation, and restoration and landscaping are not covered by the grants.
- How much electricity does it use? The county puts annual electric cost at $75 to $250 depending on the technology.
- How many of these have you installed in my town? Groundwater depth and access vary enormously between the South Shore, the North Shore and the forks.
The part that is not the installer's job
Engineering and design is contracted by you, at your expense, and it comes first. The design professional prepares the permit application and identifies any other permits needed. Some homeowners expect the installer to handle that and are surprised by the order of operations.
A licensing note
Suffolk County Code requires home improvement contractors working in the county to hold a county license. Being on the approved installer list and being licensed are two separate things, and you are entitled to see evidence of both.
Verified as of September 16, 2026. We re-check these pages quarterly. The approved-installer requirement, the payment sequence, the grant eligibility memo step and the $300–$600 maintenance and $75–$250 electricity figures were confirmed against Suffolk County's own Septic Improvement Program page, its 2026 homeowner process overview and its I/A OWTS homeowner one-pager on that date. The list itself changes — take it from the county, not from here.
All work is performed by local licensed, permitted Suffolk County-approved installers.