Islip Water Hardness & Quality Report (2026)
Water Hardness
6.7 grains per gallon
Source
reservoir
pH Level
7.8
neutral = 7.0
Lead
0.005 mg/L
✓ Below action level
TDS
233.4 mg/L
Est. Daily Cost
$0.31
energy & soap waste
Source: USGS Water Quality Portal · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In Islip, your appliances are currently losing 15% efficiency due to mineral buildup.
| Appliance | In Islip | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 5.8 yrs | 8.5 yrs | -32% |
| Washing Machine | 9.3 yrs | 12 yrs | -22% |
| Water Heater | 11 yrs | 15 yrs | -27% |
Regional Water Comparison
How Islip compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Islip, New York | 115 mg/L | 5.5 ppt | 🟡 Moderately Hard | reservoir |
| East Islip, New York | 171 mg/L | 8.2 ppt | 🟠 Hard | reservoir |
| Bay Shore, New York | 170.5 mg/L | 8.1 ppt | 🟠 Hard | reservoir |
| North Bay Shore, New York | 174 mg/L | 8.3 ppt | 🟠 Hard | reservoir |
| Central Islip, New York | 114.5 mg/L | 5.5 ppt | 🟡 Moderately Hard | reservoir |
National Benchmark
How Islip compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Islip | 115 mg/L | 🟡 Low |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Islip's Water Unique?
Local geology and source profile
Islip, New York, in Suffolk County — an unincorporated Suffolk County community on the Great South Bay adjacent to Bay Shore and East Islip, on the South Shore of Long Island west of Fire Island — receives its municipal water from the Islip Water District, drawing from the Magothy Aquifer through production wells in central Suffolk County.
The moderately hard 115 mg/L hardness and TDS of 233.4 mg/L reflect the Islip area Magothy Aquifer at intermediate well depths — similar to the Wantagh Nassau County Magothy reading (121 mg/L, TDS 254). The Magothy Aquifer beneath central-south Suffolk County is the primary production zone, with the Cretaceous Magothy Formation calcareous sand producing moderate hardness. The Islip wells are in a relatively clean zone of the South Shore aquifer, away from the deeper salt interface.
At 115 mg/L, Islip's water is moderately hard — scale builds in kettles and appliances over months, dishwashers benefit from rinse aid, and faucet aerators need periodic cleaning. Quarterly descaling is appropriate. The PFAS level of 5.5 ppt warrants a certified drinking water filter — the Pilgrim Psychiatric Center (West Brentwood) legacy, the Republic Airport (East Farmingdale — AFFF legacy in the central Suffolk aquifer), and the Long Island South Shore PFAS complex contribute to Islip's readings.
Geology & Source: Islip in Suffolk County draws from the Islip Water District on the Magothy Aquifer (central Suffolk County, Long Island) — the Magothy consists of Cretaceous Magothy Formation calcareous sand (intermediate-depth central Suffolk zone) — Long Island central Suffolk Cretaceous Magothy Aquifer produces moderately hard water at 115 mg/L with TDS 233 mg/L in this Suffolk County New York community.