Cesspool, Septic, or Sewer? How to Find Out What’s Actually Under Your Long Island Home

Roughly 74% of Suffolk County homes are not connected to a public sewer. Many owners genuinely don’t know what they have — until something backs up. Here’s how to find out before that day.

Check the records first

Suffolk County’s Department of Health Services keeps sanitary records for many properties, and town building departments often have certificates of occupancy that mention the wastewater system. Our free Home System Risk Check pulls parcel and sewer district data automatically for your address.

Signs you’re on a cesspool or septic system

No sewer charge on your tax bill, a cleanout or concrete cover in the yard, unusually green patches of lawn, and homes built before your street’s sewer district was formed are all strong indicators. Pre-1973 homes are especially likely to have block cesspools, which are now failing across the island.

Why it matters for your wallet

A failed cesspool can be a five-figure replacement, and Suffolk County’s grant programs for upgrading to low-nitrogen systems have waiting lists. Knowing what you have — and its condition — turns a future emergency into a planned decision.