The home inspector’s report says “septic system, appears functional.” The seller’s disclosure says “cesspool.” The pump company that came out last year wrote “cess pit” on the invoice. On Long Island all three can describe the same backyard, which is why it pays to know what is actually down there.
Two different machines
| Cesspool | Septic tank system | |
|---|---|---|
| What it is | One precast ring, or on older houses brick or block, with open sides | A sealed tank, followed by a leaching pool or drain field |
| What happens to solids | They settle in the bottom of the ring | They settle in the tank and stay there until pumped |
| What happens to liquid | It seeps out through the sides and bottom into the sand | It leaves the tank through a T-shaped outlet and soaks in at the leaching pool |
| Allowed as a replacement in Suffolk | No, since July 2019 | Yes, at minimum |
Sewertech describes a cesspool simply: the liquid seeps into the ground while the heavier waste sinks and stays behind. In a septic tank, the EPA says the outlet is shaped like a T to keep sludge and scum from flowing out to the drain field. That one fitting is most of the difference.
Why so many cesspools here
Suffolk has prohibited building traditional cesspools since 1973, according to The East Hampton Star’s report on the 2017 county law. What the old rules still allowed was replacing a failed cesspool with another one. That loophole closed in July 2019. In between, generations of houses kept their rings, which is how the county’s 2020 wastewater plan still counted 252,530 cesspool-only systems out of about 365,000, as The Suffolk Times reported in 2024.
How to tell which one you have
- Old paperwork. Pump-out invoices and home inspection reports often say. A mention of inlet or outlet baffles points to a septic tank, since a cesspool has none.
- Ask the pump company. The person who has had the lid off knows. Ask them to write it on the invoice next time.
Why it changes your bills
A cesspool has nowhere to hold solids back, so they build up where the liquid is trying to leave. Antorino and Sons says cesspools typically need service every one to two years under normal use, against two to three for a septic tank, even though a single pump-out costs about the same.
When the walls are brick or block
Age matters too. A 2013 27east report quoted Emil Norsic and Son on the East End saying older cesspools were built of red brick, cement block or both, while precast concrete cylinders do not collapse. The Long Island Liquid Waste Association, in the same coverage, said block cesspools should not be pumped out, because without the liquid pushing outward they can fall in, and called replacement the only full way to remove the risk. If yours is block, tell the pump company before they open it.