Short answer: No active county sewer district covers Oakdale on the county's GIS layer, so homes here use cesspools, septic tanks or I/A systems unless a village or private plant serves them. 98% sits in a proposed sewer district, which can rule out the septic grants.
Oakdale in numbers
| Town | Town of Islip |
|---|---|
| Area | 3.16 sq mi |
| In active sewer district | 0% |
| In proposed district | 98% · Oakdale Phase 5, Oakdale Phase 2, Oakdale Phase 1B |
| Groundwater zone | Zone VI 98% |
| FEMA flood zone | 35% |
| One-family lots / median | 1,950 / 0.32 ac |
| One-family lots outside active sewer districts | about 1,950 |
Computed 2026-11-07 from Suffolk County GIS (hamlet boundaries, sewer districts, groundwater management zones, FEMA flood zones, protection areas, tax parcels). Shares are of land area; a district boundary is not a hookup, and some village-run systems are missing from the county layer. Method and full table.
Sewer coverage
No active county sewer district covers Oakdale on the county's GIS layer, so homes here use cesspools, septic tanks or I/A systems unless a village or private plant serves them. About 98% of Oakdale is inside proposed districts (“Oakdale Phase 5”, “Oakdale Phase 2”, “Oakdale Phase 1B”). Suffolk's septic grants exclude homes in a proposed sewer district, so check the address on the county map before budgeting for an I/A upgrade. Counting lots instead of land: about 1,950 of the 1,950 one-family lots touching Oakdale lie outside any active sewer district, and those homes rely on on-site systems. Next door: Great River (57% sewered, median lot 0.49 ac); West Sayville (0% sewered, median lot 0.26 ac); Bohemia (0% sewered, median lot 0.46 ac). By active-sewer share Oakdale ranks 77 of the 165 Suffolk hamlets and villages we measured.
Groundwater, lots and flood exposure
Groundwater management Zone VI: Article 6's minimum lot for a new home on an on-site system here is 40,000 sq ft, unless the density is met another way or an exemption applies. County parcel records show 1,950 one-family lots touching Oakdale, with a median of 0.32 acres (about 13,800 sq ft), below that minimum and the 98th-largest median lot in our Suffolk table. 35% of the land is in FEMA's 1%-annual-chance flood zone.
Before planning an I/A upgrade in Oakdale, confirm whether your street is in the proposed district; if it is, the county and state grants may not apply. With 35% of the land in the flood zone, ask whether groundwater flows back into the cesspool after pumping; in Suffolk that is a failed-system condition.
Who handles what in Oakdale
- Building and electrical permits: Town of Islip
- System approvals and grants: SCDHS, 631-852-5700 (permits) / 631-852-5811 (grants)
Frequently asked questions
Is Oakdale on public sewer?
Generally not: no active county sewer district covers Oakdale on the county's map.
Can Oakdale homeowners get septic grants?
Many can't: about 98% of Oakdale is inside a proposed sewer district, and the Suffolk and state grants exclude homes there. Homes outside it can apply for up to $20,000 from Suffolk and up to $25,000 from the state. Check the address on the county's eligibility map.
County rules, licensing and grant steps: Town of Islip overview, septic grants, replacement rules. More in Islip: Bohemia, Sayville, Bayport, Islip.
Sources
Each source was re-read on November 7, 2026. Program amounts and rules change; the agency page is the authority.
- Suffolk County GIS Viewer map service (hamlets, villages, sewer districts, groundwater zones, flood zones, tax parcels)
- Suffolk County Sanitary Code, Article 6 (amended 12/1/2020)
- Suffolk County: Septic Improvement Program information
- Suffolk County: SIP property eligibility lookup
Need cesspool or septic work in Oakdale?
Submit a request with your address. We match it to an independent, licensed Suffolk County operator who serves that address; the operator confirms the time and price with you.
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