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Cesspool Replacement Cost on Long Island (Suffolk County Prices)
Last reviewed October 17, 2026 · Official sources linked throughout
For a typical Long Island home in Suffolk County (1–4 bedrooms), the county's published installer base prices for a nitrogen-reducing I/A system range from $15,275 to $45,025, with a median of $25,688, when the existing leaching structure can be reused. [cost ranking] New leaching or a pressurized drainfield costs more.
Published price ranges by scenario
These numbers summarize every price in Suffolk County's SIP Vendor Cost Ranking (rev. 2025-11-06), across all approved technologies. They're base-price estimates: sales tax, engineering and design are not included, and actual costs vary by site. [4-BR]
1–4 bedroom home [cost ranking]
| Scenario | Lowest | Median | Highest | Prices |
|---|---|---|---|---|
| I/A system reusing the existing leaching structure | $15,275 | $25,688 | $45,025 | 126 |
| I/A system with a new gravity leaching structure | $19,950 | $29,104 | $50,275 | 126 |
| I/A system with a pressurized shallow drainfield | $24,350 | $33,937 | $74,069 | 125 |
5-bedroom home [cost ranking]
| Scenario | Lowest | Median | Highest | Prices |
|---|---|---|---|---|
| I/A system reusing the existing leaching structure | $17,115 | $26,935 | $48,000 | 132 |
| I/A system with a new gravity leaching structure | $22,590 | $31,488 | $58,000 | 132 |
| I/A system with a pressurized shallow drainfield | $28,245 | $35,868 | $91,274 | 132 |
6-bedroom home [cost ranking]
| Scenario | Lowest | Median | Highest | Prices |
|---|---|---|---|---|
| I/A system reusing the existing leaching structure | $17,750 | $27,585 | $50,425 | 97 |
| I/A system with a new gravity leaching structure | $23,275 | $32,400 | $64,005 | 97 |
| I/A system with a pressurized shallow drainfield | $29,425 | $38,025 | $108,480 | 97 |
What drives the price
According to the county, installation costs depend on soil type, depth to groundwater, site constraints like equipment access and existing structures, site restoration, tank size (based on bedrooms), and the I/A technology chosen. [source]
Ongoing costs after installation
- Operations and maintenance contract: about $300–$600 a year
- Pumping: average system every 3 years, about $500 each time
- Electricity: about $75–$250 a year depending on system type
- Repairs: blower about $450 every 10 years, recirculation pump about $700 every 10 years, floats about $100 every 5–10 years
Figures from the county's "What Homeowners Should Know About I/A OWTS" sheet, based on vendor information. [source]
How much will grants cover?
Combined county and state grants can reach up to $45,000. [flyer] At the published median prices above, grants at their maximum could cover most or all of the base installation price, though not engineering, permits, sales tax or landscaping. Use the grant checker for an estimate based on your situation.
Nassau County
This guide covers Suffolk County. Nassau County runs a separate program (SEPTIC) that the state describes as providing up to $20,000 for failing systems. [DEC]
Get quotes from county-approved installers
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Independent guide. Not affiliated with, endorsed by, or operated by Suffolk County, New York State, or any installer. This page is general information, not legal or financial advice.
Sources
- Suffolk County – SIP Vendor Cost Ranking, 4-bedroom home (PDF) — rev. 2025-11-06
- Suffolk County – SIP Vendor Cost Ranking, 5-bedroom home (PDF) — rev. 2025-11-06
- Suffolk County – SIP Vendor Cost Ranking, 6-bedroom home (PDF) — rev. 2025-11-06
- Suffolk County DHS – What Homeowners Should Know About I/A OWTS (PDF) — dated 5-5-2026
- Suffolk County – “Suffolk County’s Septic Grant Program” flyer (PDF) — revised 9-29-2026
- NYS DEC – State Septic System Replacement Fund Program (SSRP) — page accessed Oct 17, 2026
Last reviewed October 17, 2026. Program rules change; always confirm with Suffolk County Department of Health Services (631-852-5811, [email protected]).