Area guideGreenlawn
Water Damage Restoration Help in Greenlawn, NY
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The hamlet of Greenlawn · Town of Huntington
Water in the basement, a burst pipe, or sewage backing up into the house? Call and we'll connect you with a local specialist who covers Greenlawn, even if you don't know the cause yet.
Water doesn't stay where it lands. It soaks into drywall, insulation and flooring, and mold can start within 24 to 48 hours.
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Only 1 of the 4,396 addresses in Greenlawn is in FEMA's flood zone, so the water that damages homes here usually comes from their own pipes and drains, not from a flood.
Greenlawn at a glanceTap a figure to see it on the map
Flood risk: LowFlood zone. 1 of the 4,396 addresses here is inside FEMA's mapped flood zone.
If your home is in it, most mortgage lenders must require flood insurance. That is a separate policy from homeowner's insurance, which usually covers a burst pipe or leaking appliance.
Each square is about 500 ft across. Color shows how many of its addresses are mapped inside the zone:
- All
Groundwater. At 15 of the 4,396 addresses measured here, groundwater is within 14 ft of the surface, close enough to reach a basement floor.
In those basements, water can seep up through the floor and come back after pumping. At the other 4,381, water in a basement usually comes in from above.
Each square is about 500 ft across. Color shows the typical depth under its addresses (USGS map, spring 2013):
- Within 10 ft13
- 10 to 14 ft2
- 14 to 25 ft12
- Deeper than 25 ft4,369
Sewer. 159 of the 4,396 addresses in Greenlawn have a county sewer main mapped past them. That does not mean every house is connected.
At the other 4,237, a backup means a cesspool or septic tank, and a pumping company. On a main, it means a plumber, or the sewer district if the main is blocked.
Each square is about 500 ft across. Color shows how many of its addresses have a mapped main:
- Fewer than half
- Half or more
What is happening at your home?
Other water emergencies we cover
Not sure which one fits? Call (631) 440-4144 and tell us what you see.
Why water gets into Greenlawn homes
None of Greenlawn's built-up land is in FEMA's flood zone, so floodwater from outside is not the main threat to homes here. For homes here, the risks to know are water getting into the basement, a pipe that freezes and splits, a full or failing cesspool and old plumbing leaking inside the walls.
- Water in the basement. Pumping the water out is only half the job: the basement has to be dried and the source handled, usually with a sump pump or sealing, or the water comes back. Greenlawn's water table averages 137 ft, but on some streets it sits close enough to wet a basement floor, so whether seepage is a risk depends on the street. Basement Flooding help in Greenlawn
- A burst pipe. A frozen pipe that has not split yet can be saved: open the tap and warm the line gently from the tap end back, never with a flame. Fuel oil heats about 36% of Greenlawn's homes, so a missed delivery in a cold week can leave a house without heat long enough for a pipe to freeze and split. Frozen Pipe Burst help in Greenlawn
- Sewage coming up a drain. Standard homeowners policies usually exclude sewage backup unless a water-backup endorsement was added, so check yours and photograph the damage before cleanup starts. In Greenlawn, 4,237 of 4,396 addresses send their wastewater to a cesspool or septic tank in the yard, with no sewer main mapped past them, and a system that is full or failing has nowhere to send it but back into the house. Cesspool Overflow help in Greenlawn
- A leak in a wall or ceiling. To check for a hidden leak, turn off every tap and watch the water meter; if it still moves, water is going somewhere it should not. More than half of Greenlawn's houses predate 1970, so many still have original supply and drain lines, where a slow leak can run behind a wall for weeks before it shows. Ceiling & Roof Leak Water Damage help
Insurance and safety guidance from FEMA FloodSmart, the CDC and the Red Cross. How we measured the figures.
Street by street in Greenlawn
See how many of its addresses are mapped inside the FEMA flood zone, how deep groundwater is mapped under it, and whether a sewer main is mapped past it.
209 streets, from county address records. Nothing you type is sent anywhere.
Streets with a mapped sewer main
County records map an active sewer main past 159 of 4,396 address points in Greenlawn. On 2 streets nearly every address has one; the largest:
- Otego Pl — 8 addresses
- Unadilla Pl — 8 addresses
Quick facts — Greenlawn
Flood and storm
- FEMA flood zone
- X-shaded (500-yr)
In an emergency
- Nearest fire department
- Greenlawn Fire Department
- Nearest emergency shelter
- Walt Whitman High SchoolNot every shelter opens for every storm, and the nearest may stay closed. Suffolk County announces which ones open; follow its alerts and local news before you go.
- ZIP code
- 11740
Homes here
- Sewer status
- Unsewered (Cesspool/Septic)
- Home heating fuel
- 36% fuel oil Utility gas heats 49% of occupied homes in Greenlawn. Census estimates; the oil figure is within 7 points. An oil tank can float or tip in a flood and spill. That is a separate cleanup from the water (NYS DEC). In a cold snap, an empty tank means no heat.
- When homes were built
- Spread across decades The highlighted 1950s band is the largest, at 28%, but its lead over the 1960s band (26%) is inside the Census margin of error (4 points), so no decade clearly leads in Greenlawn. Most homes here are over 30 years old. Past that age, an insurance-industry study (IBHS) found supply and drain pipe problems three times as likely.
Sources: FEMA NFHL / NOAA SLOSH, US Census ACS, USDA SSURGO, Suffolk County records. Verified 2026-10-18. How we measured this.
Greenlawn and nearby areas
None of the other 6 areas compared here has a smaller mapped floodplain share than Greenlawn.
- Centerport 7.1%
- Huntington 0.5%
- Greenlawn 0.0%
- Dix Hills 0.0%
- East Northport 0.0%
- Elwood 0.0%
- Huntington Station 0.0%
Share of developed area inside FEMA's mapped floodplain, largest first.
5 of the other 6 areas compared here have shallower average groundwater than Greenlawn.
- Centerport 70 ft
- Huntington 107 ft
- Huntington Station 118 ft
- Elwood 127 ft
- Dix Hills 129 ft
- Greenlawn 137 ft
- East Northport 153 ft
Average depth to groundwater, shallowest first.
Greenlawn has the highest average ground of the 7 areas compared here.
- Centerport 82 ft
- Huntington 133 ft
- Huntington Station 184 ft
- Elwood 201 ft
- Dix Hills 201 ft
- East Northport 202 ft
- Greenlawn 205 ft
Average height above sea level, lowest first.
Across the 6 areas around Greenlawn the ground elevation averages 167 ft. Here it is 205 ft. Greenlawn sits on higher ground than the areas around it. The second gap is water table: 137 ft against 117 ft next door. Groundwater sits deeper under Greenlawn than under the areas around it.
Compared with the areas around Greenlawn. How we measured them.
Frequently asked questions about Greenlawn
Is Greenlawn in a flood zone?
Greenlawn has no developed land inside a FEMA special flood hazard area, per FEMA's flood map (NFHL). The flood map describes surface flooding only, so it says nothing about groundwater, sewer or plumbing failures.
Does Greenlawn have public sewer, or cesspools?
Greenlawn is unsewered — nearly every property runs on its own cesspool or septic system.
How deep is the water table in Greenlawn?
The measured water table runs about 137 ft below the surface on average across Greenlawn. It is mapped within 10 ft at 13 of 4,396 addresses and within 25 ft at 27.
How old are homes in Greenlawn?
The average home in Greenlawn is about 63 years old, and 67% of the housing stock predates 1970 — older plumbing and unwaterproofed foundations are a common factor in local water damage.
About the figures for Greenlawn
Check them at the source
Who to call for water damage in Greenlawn
(631) 440-4144Tell us what is happening. We connect you with a local specialist who covers Greenlawn.