Nassau County & western Suffolk
Backwater Valve Installation on Long IslandSewer Check Valves for Sewered Homes
All Island Plumbing, Heating & Cooling is a plumbing company at 5788 Merrick Rd, Suite 203, Massapequa, NY 11758, installing backwater (sewer check) valves in homes on a public sewer across Nassau County and the Towns of Huntington, Babylon and western Islip. Call (631) 644-2084. We answer calls 24/7 and are open Monday through Saturday (closed Sunday).
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- Local office · Merrick Rd, Massapequa
- Nassau County & western Suffolk
- Licensed & insured across Long Island
- Answering calls 24/7 · Open Mon–Sat, closed Sunday
A backwater valve is a check valve on the house sewer line. Waste flows out normally. If the public sewer backs up, the valve closes so sewage can't flow back into the house through basement floor drains, low toilets and tubs.
Who it's for
- Homes on a public sewer. A home on a cesspool or septic system doesn't have a street sewer to back up from.
- Houses with drains below street level: basement floor drains, basement bathrooms, laundry tubs
- Low-lying and flood-zone streets, where storm surge and heavy rain can overload the sewer system
What we do
- Install backwater valves on the house sewer line, sized to the line
- Install them where they can be reached and maintained
- Check and clear existing backwater valves that stick or don't close
What we don't do
- Storm-drain check valves in the street (those belong to the village, town or county)
- Cesspool or septic work of any kind beyond clearing the line to an existing septic tank
Why it matters here
In Superstorm Sandy, the line to Nassau County's Bay Park plant was breached and sewage backed up at manholes and through basement drains into homes, according to the Baldwin NY Rising plan. The Five Towns plan says sewers in Woodmere, Hewlett and nearby communities backed up into streets and the basements of some homes when Bay Park lost power. In Freeport, nearly 3,500 homes had saltwater flooding, and the village has since added check valves to its storm drains. A backwater valve on your own house line is the same idea for the sanitary side.
FEMA's flood maps show how much of each place is high-risk. Laying the current map over Census boundaries puts about 42% of the Village of Freeport and 9% of West Babylon in the high-risk zone, but none of the Village of Hempstead, Levittown or Hicksville. Your town page lists the share for your area.
How it works
- Confirm you're on a public sewer and find where the house line leaves the building.
- Pick the spot. The valve has to protect the low drains, and it has to stay reachable for cleaning.
- Install and test it. Valves need occasional cleaning so debris doesn't keep them from closing.
Where
Backwater Valve Installation near you
Town pages with local facts for this service, plus every community we serve.
Other plumbing services
Questions
Backwater Valve Installation FAQ
Is a backwater valve the same as a backflow preventer?
I'm on a cesspool. Do I need one?
Does a backwater valve need maintenance?
Sources:Baldwin NY Rising Community Reconstruction Plan (Bay Park line breach, sewage backups at basement drains); Five Towns NY Rising Community Reconstruction Plan (sewer backups into streets and basements); Newsday, "Where six Long Island communities stand now, five years after Sandy" (2017; Freeport homes, storm-drain check valves); FEMA National Flood Hazard Layer overlaid on U.S. Census 2020 place boundaries (Atlas, Nov. 2–3, 2026).