GuideSuffolk County
Cesspools by area: what the sewer map shows
How many addresses in each Suffolk County area have no county sewer main mapped past them, where that count holds, and who to call when sewage backs up.
Updated October 27, 2026. From public map and claims data for Suffolk County; how the figures are made is on the methodology page.
What the sewer map can tell you
Suffolk County maps its sewer mains. A house with no main mapped past it sends its wastewater to a cesspool or septic tank in the yard, and when that system is full or failing, sewage has nowhere to go but back up through the lowest drain in the house.
The county's map leaves out sewer systems that some towns and villages run themselves, so in those places a missing main says nothing. We give a count only where the map accounts for at least half of the sewer coverage on record for the area.
Addresses with no sewer main mapped, area by area
| Area | No sewer main mapped | Share of addresses |
|---|---|---|
| Commack | 11,777 of 12,265 | 96% |
| Deer Park | 9,453 of 9,765 | 97% |
| Huntington Station | 9,393 of 9,656 | 97% |
| Smithtown | 8,393 of 8,518 | 99% |
| Central Islip | 8,022 of 9,354 | 86% |
| East Northport | 6,923 of 7,068 | 98% |
| East Patchogue | 6,435 of 7,238 | 89% |
| Selden | 5,887 of 6,453 | 91% |
| Ronkonkoma | 5,855 of 5,928 | 99% |
| Sayville | 5,214 of 5,830 | 89% |
| Kings Park | 4,935 of 6,067 | 81% |
| Greenlawn | 4,237 of 4,396 | 96% |
| Bayport | 3,643 of 3,741 | 97% |
| South Huntington | 3,374 of 3,442 | 98% |
| Oakdale | 3,073 of 3,249 | 95% |
| North Babylon | 2,453 of 5,996 | 41% |
| Baywood | 2,169 of 2,192 | 99% |
| West Sayville | 2,005 of 2,029 | 99% |
Addresses are the county's address points; a main counts as mapped past an address when the county's sewer layer puts one within 45 m of it. The other 25 areas we cover have no count here: most of their addresses are on a sewer, fewer than 500 are off one, or the county map leaves out the system that serves them. Sources and limits.
Your own address
The address check shows whether a county main is mapped past one address, and how deep groundwater was mapped there. Where groundwater is mapped close to the surface, it can crowd a cesspool ring.
When sewage comes back up: two jobs
The system in the yard and the house are different work, usually by different firms. Pumping or repairing the cesspool is septic work: call a cesspool company for that, because our line does not arrange pumping. If sewage has come into the house, cleaning it up is restoration work, and that is the call we connect with a specialist covering your part of Suffolk County.
What to do first, the county's rule for replacing a failed cesspool and the grants toward it are on our cesspool overflow page.
More for Suffolk County
Who to call for water damage in Suffolk County
(631) 440-4144Tell us what is happening. We connect you with a local specialist who covers your part of Suffolk County.