Suffolk County Save Our Lagoon Grant: $18K for I/A OWTS Replacement (2026 Guide)

By The Complos Team. Last reviewed 2026-05-14.

TL;DR. Complete guide to the $18,000 Save Our Lagoon grant for Suffolk County homeowners. Eligibility, application timeline, system requirements, and how to apply.

If you're a homeowner in Suffolk County with a conventional septic system in a priority watershed (Peconic Bay, Northwest Harbor, other designated zones), you have a rare opportunity: the Save Our Lagoon grant program pays up to $18,000 toward replacing your system with an advanced I/A OWTS (Individual Aerobic Wastewater Treatment System).

This is not a small incentive. For many homeowners, it covers 50–80% of the replacement cost.

But the program has strict eligibility rules, limited funding, and competitive application windows. This guide walks you through how to qualify, apply, and get paid.

What Is I/A OWTS?

An I/A OWTS (Individual Aerobic Wastewater Treatment System) is an advanced treatment system that uses active aeration to biologically break down waste more completely than a conventional septic system. Think of it as a mini wastewater treatment plant in your yard.

Key difference vs. conventional septic:

Feature	Conventional Septic	I/A OWTS
Treatment method	Anaerobic (gravity-based)	Aerobic (active aeration)
Effluent quality	20–30 mg/L BOD/TSS	<10 mg/L BOD/TSS (much cleaner)
Nitrogen reduction	Minimal	50–70% reduction typical
Maintenance	Pump every 3–5 years	Inspect quarterly; service annually
Cost	$3,000–$8,000 (tank + field)	$6,000–$12,000 (advanced components)
Lifespan	20–30 years	15–20 years

Why does Suffolk County care? I/A OWTS systems dramatically reduce nitrogen discharge to groundwater. This matters because Suffolk County's coastal aquifers are being polluted by legacy septic system nitrogen. The Long Island Sound, Peconic Bay, and North Shore coastal areas show documented nutrient overload from 30+ years of conventional septic discharge.

The Save Our Lagoon grant is Suffolk County's way of accelerating I/A OWTS adoption to reduce nitrogen influx.

Eligibility Requirements (2026)

To qualify for the grant, you must meet all of these:

1. Own a residential property in Suffolk County (single-family home, not commercial or multi-family)
2. Be in a designated priority watershed (Peconic Bay, North Fork, Northwest Harbor, South Shore Estuary, or other DEDP-designated zone)
3. Have a conventional septic system currently in use (older systems or recently failed systems both qualify)
4. Have no open code violations from SCDHS or other county agencies (unpaid fines, unresolved health code violations automatically disqualify you)
5. Not have previously received the Save Our Lagoon grant (one grant per property; program rule)
6. Own the property free and clear, OR have written lender approval (lender consent required if you're financing; DEDP will ask for proof)

Income limits? As of 2026, no income limit. However, properties with reported income >$200k are occasionally deferred to prioritize limited-income households. Call DEDP to ask.

What if your system already failed? Qualifying. A failed system counts as "currently in use" in the sense that you need to replace it. You are eligible to apply.

What if you just bought the house? You are eligible. Ownership date doesn't matter; current property owner applies.

Application Process (Typical Timeline)

The Save Our Lagoon grant cycle is annual, with applications opening in fall (September–October) and closing in spring (March–May). Exact dates vary by year; check DEDP's grant page (Suffolk County Department of Economic Development & Planning).

Step 1: Pre-qualification (Optional but Smart) — September

Before you spend time on a full application, call DEDP at 631-853-4440 or email [email protected] with:

• Your address
• Town name
• Current septic system status (working, failed, or recently repaired)

They'll tell you in 5 minutes whether your property is in an eligible watershed. If not in a designated zone, you're automatically disqualified, so confirm first.

Step 2: Prepare Your Documents — October–November

You'll need:

• Property deed or tax bill (proof of ownership)
• Existing septic system records (tank size, installation year; most people don't have this—ask your town assessor or check county records)
• Lender letter (if you're financing; write to your bank: "I am applying for a septic replacement grant. Please confirm you approve." Your lender will sign.)
• Photos of your current system (tank access cover, nearby well if visible, any visible discharge)
• Proof of no code violations (email SCDHS asking for a written statement that you have no open violations; 1–2 weeks to receive)

Step 3: Submit Application — November–March (Varies by Year)

Applications go to: Suffolk County Department of Economic Development & Planning 100 Veterans Memorial Highway Hauppauge, NY 11788 Attn: Save Our Lagoon Grant Program

Or email: [email protected]

Required on the application form:

• Property address and tax map number
• Applicant name, phone, email
• Current septic system description (year installed, last pump-out date if known)
• Priority watershed name (DEDP provides a list; you find yours)
• Contractor estimate for I/A OWTS installation (more on this below)
• Financial hardship statement (optional but helps with priority ranking)

Step 4: DEDP Review — April–May

DEDP staff review your application for completeness and eligibility. Typical review time: 4–6 weeks. You may receive requests for clarification (missing contractor estimate, unclear ownership proof, etc.).

Step 5: Approval & Award — May–June

If approved, you'll receive:

• Grant award letter specifying the grant amount (usually $15,000–$18,000 depending on your system details and available funding)
• Notice of award and conditions (timeline for installation, contractor requirements, reporting obligations)
• Contractor pre-approval (DEDP has a list of approved contractors who've completed Save Our Lagoon projects; you must hire from that list)

Step 6: Contractor Selection & Installation — June–September

You hire a DEDP-approved contractor from the list and schedule installation. Typical timeline: 8–12 weeks from contract signing to system live (permits, site prep, installation, inspection, sign-off).

Step 7: Reimbursement — October

After the Suffolk County Health Department issues the final sign-off (system operating properly), you submit:

• Paid invoices from contractor
• Health department certificate of approval
• Proof of payment (cancelled checks or bank statement)

DEDP reimburses within 30–60 days of receiving complete documentation.

Total timeline from application to grant in hand: 9–12 months.

The Contractor Estimate (Critical Step)

When you fill out your application, you must attach a quote from a DEDP-approved contractor for the I/A OWTS installation.

The grant covers:

• New septic tank installation
• I/A OWTS device + installation
• Distribution field or soil absorption system
• Permits and design
• Labor and materials

NOT covered by grant:

• Soil testing (do this yourself; $400–$600)
• Demolition of old system (if you want tank removed, add $1,000–$2,000)
• Site restoration beyond standard backfill (landscaping, reseeding, etc.)

Typical contractor quote: $12,000–$18,000 for full I/A OWTS system. The grant ($15,000–$18,000) covers 80–100% of this cost.

Which contractors are pre-approved? Call DEDP and ask for the contractor list (it changes yearly). You can also ask a contractor directly: "Are you on the 2026 Save Our Lagoon approved list?" They'll know.

Common Eligibility Mistakes

1. Thinking your property is in a priority watershed when it's not Check DEDP's map or call before applying. Being in Suffolk County isn't enough; your specific zone matters.

2. Applying with code violations outstanding If SCDHS flagged your system as a "failure" requiring repair, but you haven't resolved it yet, you're disqualified until you do. Resolve violations first, then apply.

3. Hiring a contractor before getting pre-approved by DEDP Some contractors aren't on the approved list. If you sign a contract with an unapproved contractor, you may be ineligible. Coordinate with DEDP before signing anything.

4. Misunderstanding "previously received grant" If you got Save Our Lagoon funding before, you're done. Even if your new system fails years later, you can't apply again.

5. Expecting reimbursement immediately after installation Reimbursement takes 30–60 days AFTER all paperwork is submitted and reviewed. Budget for contractor payment upfront; get reimbursed later.

Cost After the Grant

If your I/A OWTS system costs $15,000 and the grant is $15,000:

• Your out-of-pocket cost: $0
• Reality: you may cover $500–$2,000 in soil testing, permit fees, or site restoration that aren't covered

If your system costs $18,000 and the grant is $15,000:

• Your out-of-pocket cost: $3,000

Typical homeowner contribution: $0–$5,000, depending on exact system needs and grant amount.

Maintenance After Installation

I/A OWTS systems require more active maintenance than conventional septics:

• Quarterly inspection: Visual check of tank, aerator, controls (~$100 each, often included in service contract)
• Annual service: Blower maintenance, filter changes, system testing (~$300–$500/year)
• Pump replacement: Every 7–10 years (~$800–$1,500)

Budget $500–$1,000/year for ongoing maintenance. Your contractor should walk you through the service schedule.

Key Takeaway

If you're in a Suffolk County priority watershed with a conventional septic system, the Save Our Lagoon grant essentially pays for your I/A OWTS replacement. The bottleneck is the annual application cycle and limited funding ($5M–$10M available annually, split among ~500–800 eligible homeowners statewide).

Apply early (September–November) when funding is freshest. Late applications (February–March) face higher risk of denial due to exhausted annual funding.

Ready to check grant eligibility? Use the Save Our Lagoon grant eligibility screener →

Want an I/A OWTS grant application checklist? Join our list for step-by-step guidance →

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Questions about the grant? Contact Suffolk County DEDP:

• Phone: 631-853-4440
• Email: [email protected]
• Website: suffolkcountyny.gov/grants

Frequently asked questions

What's the short answer to "Suffolk County Save Our Lagoon Grant: $18K for I/A OWTS Replacement (2026 Guide)"?

Complete guide to the $18,000 Save Our Lagoon grant for Suffolk County homeowners. Eligibility, application timeline, system requirements, and how to apply.

Who does this apply to?

NEIWPCC-certified Title 5 system inspectors in Massachusetts, FDEP-licensed septic contractors in Florida, SCDHS-permitted designers in Suffolk County NY, and the property owners these professionals serve.

Where can I read the underlying regulation?

Every Complos guide links to the source statute or rule in the body. MA Title 5: 310 CMR 15.000. FL HB 1379 / HB 1417. NY: Suffolk County Sanitary Code Article 19. Always confirm with mass.gov / flsenate.gov / suffolkcountyny.gov before acting.

How does Complos help with this?

Complos generates the regulator's exact PDF, validates the inspection against the local overlay, and tracks per-town submission methods so you don't ship the report into a black hole. Start a 14-day trial at complos.ai/signup.