Grant eligibility checker
Answer practical property questions and see what may need official review.
Check my eligibilityClear, independent homeowner guidance
Suffolk County Septic Grant and Replacement Help
Understand possible grants, estimate an I/A system project and take the next step with confidence.
Request installer quotesResults are estimates. Grant approval is determined by the applicable government program.
Potential combined assistance
Up to $45,000
Eligible homeowners may qualify for up to $45,000 in combined county and state assistance, subject to program eligibility, eligible project costs and available funding.
Last reviewed: September 2026 · View the official Suffolk County program source
Start with useful answers
Plan before you share your details
Use either tool without entering your name, email or phone number.
Replacement cost estimator
Build a planning range around your home, current system and site conditions.
Get my cost estimateWhat changes underground
Three systems, different levels of treatment
Cesspool
Collects wastewater and lets it seep into surrounding soil with minimal treatment.
Conventional septic
Settles solids in a tank before liquid moves to a leaching area.
I/A OWTS
Adds advanced treatment designed to reduce nitrogen before dispersal.
Compare the systemsSimplified illustration — not an engineering plan.
A clearer path
Learn first. Decide second.
- Check likely eligibility
Identify answers that align and issues requiring official review.
- Estimate cost
See a broad range and the factors a site visit must confirm.
- Request introductions
Optionally share your project with participating providers.
Why quotes vary
Cost follows the property
Bedrooms influence tank size, while soil, groundwater, structures and access shape the design and installation effort.
Explore your cost factorsSoil and groundwaterEquipment accessTank size and technologyEngineering and permitsElectrical workSite restoration
Riverhead focus
Start with sewer status and the parcel
Riverhead includes defined sewer districts and many properties with private onsite systems. Confirm the parcel’s wastewater status before planning a grant-funded replacement.
Read the Riverhead guideCommon questions
Plain answers for early planning
Can a Suffolk County septic grant cover the full project?
It may cover a substantial portion of eligible costs, but not every expense is eligible. Permits, engineering, landscaping, maintenance and site-specific work may remain the homeowner’s responsibility.
Do I need an approved installer?
Grant-funded systems must be installed by a vendor on Suffolk County’s approved installer list. Confirm current status directly with the county before signing.
Is the eligibility checker an application?
No. It is an educational screening tool. Suffolk County and the applicable state program determine eligibility and approval.
What does I/A OWTS mean?
It means Innovative/Alternative Onsite Wastewater Treatment System: an advanced system that adds treatment designed to reduce nitrogen before wastewater is dispersed.
Can I use the calculators without sharing contact details?
Yes. Both tools show results before any optional installer-introduction form.
Optional next step
Want quotes for your property?
Request introductions to participating installers. Read and use every tool first — no contact details are required for calculator results.