The morning after a week of rain in Shirley, there is a dip in the backyard that was not there before, about where the cesspool cover sits. Do not walk over to look. A collapsing cesspool is a hole in the ground with nothing holding up the edges, and on Long Island people have been badly hurt and killed falling into them.
Stay off it, then call
27east’s 2013 reporting on the East End listed two Deer Park cases: a landscaper who died after falling into a six-foot-deep cesspool in 2007, and a man who fell in chest-deep in 2009 and was rescued. Emil Norsic and Son told the paper that a new depression in the ground can mean a collapse has already happened below, and that a collapse can also break a gas line.
The Long Island Liquid Waste Association’s advice from the same coverage:
- Keep cars and heavy machinery off the area, and do not use it for picnics or children’s play.
- Watch for settling or a sinkhole, and call a licensed septic company right away if you see one.
- Expect the riskiest times to be after heavy rain or snow and during the first spring thaw, when the ground is saturated.
If it is a neighbor’s cesspool or a property you do not control, Nassau’s Department of Health handles complaints about overflowing cesspools through its Community Sanitation Program at 516-227-9715.
Repair or replace
Not every failure means a whole new system. Jet Cesspool Service in Holbrook says it can dig around a collapsed ring or dome, take out the failed sections and set new rings or a new dome. A broken cover is usually one of the simpler repairs.
The line Jet draws: a pool that has failed completely, or keeps flooding even after it is pumped, usually needs replacing. In Suffolk, a replacement needs approval from the county health department, Jet adds.
What replaces it
In Suffolk, not another cesspool. Since July 1, 2019, the minimum replacement is a septic tank ahead of a leaching structure, as both the Peconic Estuary Partnership and Jet describe it. The tank holds solids back from the new leaching pool. Jet points out what happens when that fails: if a baffle breaks, solids flow into the leaching pools and clog them. New homes and the biggest renovations need a nitrogen-reducing system instead.
The old ring has to be dealt with too. Emil Norsic and Son told 27east that old pools left unfilled after a new system goes in can stay buried and hidden. Ask how the old cesspool will be pumped, filled and closed, and get it in writing.
Replacement costs from local companies
| Item | Range | Who published it |
|---|---|---|
| Typical cesspool-to-septic conversion | $10,000 to $25,000 | Antorino and Sons, Jun 2026 |
| Emergency replacement | $8,000 to $15,000 minimum, often with rush charges | Antorino and Sons, Jun 2026 |
| Percolation testing | $450 to $1,400 | Antorino and Sons, Jun 2026 |
| Permit application and inspections | $330 to $2,000 | Antorino and Sons, Jun 2026 |
| Land survey for setbacks | $330 to $900 | Antorino and Sons, Jun 2026 |
| Removing and abandoning the old system | $1,000 to $3,000 or more | Long Island Sewer and Water Main, Sep 2026 |
| Full system replacement | $10,000 to $25,000 or more | Long Island Sewer and Water Main, Sep 2026 |
Antorino and Sons says the digging and setting takes five to ten working days after permits are approved, and permits add two to six weeks.
Paying for it
Both counties pay toward a nitrogen-reducing replacement for eligible homes: up to $45,000 combined in Suffolk and up to $20,000 in Nassau. If the cesspool has already failed, ask about the grant before you sign anything. Suffolk says it prioritizes failed systems, but the approvals still come first. The steps are in our guides to Suffolk’s grants and Nassau’s.
Questions for the replacement company
- Can this ring be repaired, or does it need replacing? Show me why.
- What are you proposing to put in, and does it meet the county rule?
- Who files with the health department or building department?
- How will the old cesspool be closed?
- Does the price include restoration of the lawn, driveway or walk?
- If I want the grant, are you on the county’s installer list (Suffolk) or home improvement licensed (Nassau)?