East Setauket Water Hardness & Quality Report (2026)
Water Hardness
10.3 grains per gallon
Source
reservoir
pH Level
8.3
neutral = 7.0
Lead
0.009 mg/L
✓ Below action level
TDS
473.5 mg/L
Est. Daily Cost
$0.47
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 East Setauket, your appliances are currently losing 24% efficiency due to mineral buildup.
| Appliance | In East Setauket | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 3.8 yrs | 8.5 yrs | -55% |
| Washing Machine | 7.1 yrs | 12 yrs | -41% |
| Water Heater | 8.5 yrs | 15 yrs | -43% |
Regional Water Comparison
How East Setauket compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ East Setauket, New York | 177 mg/L | 8.4 ppt | 🟠 Hard | reservoir |
| Setauket-East Setauket, New York | 118 mg/L | 5.7 ppt | 🟡 Moderately Hard | reservoir |
| Stony Brook, New York | 87.5 mg/L | 4.3 ppt | 🟡 Moderately Hard | reservoir |
| Saint James, New York | 109.5 mg/L | 5.3 ppt | 🟡 Moderately Hard | reservoir |
| Centereach, New York | 112.5 mg/L | 5.4 ppt | 🟡 Moderately Hard | reservoir |
National Benchmark
How East Setauket compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ East Setauket | 177 mg/L | 🟠 Moderate |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes East Setauket's Water Unique?
Local geology and source profile
East Setauket, New York, in Suffolk County — a Suffolk County community adjacent to Stony Brook and Setauket in the Three Village area of north-central Long Island, home of the State University of New York at Stony Brook — receives its municipal water from the Suffolk County Water Authority (SCWA), drawing from the Long Island Aquifer (Upper Glacial and Magothy Aquifers) through local well fields in north-central Suffolk County.
The very hard 177 mg/L hardness and elevated TDS of 473.5 mg/L reflect the north-central Suffolk County Long Island Aquifer's relatively harder character — harder than Kings Park (161.5 mg/L) in north Suffolk, suggesting the East Setauket area draws from deeper Cretaceous Magothy Aquifer horizons with higher mineral content, or encounters locally harder glacial outwash zones in the Three Village area.
At 177 mg/L, East Setauket's water is very hard — scale builds rapidly in kettles and appliances, a water softener is strongly recommended, and water heaters should be descaled annually. The PFAS level of 8.4 ppt warrants a certified drinking water filter — the Brookhaven National Laboratory (Suffolk County — nuclear facility, historic PFAS in the Long Island aquifer system), the Republic Airport AFFF plume, and the Nassau-Suffolk Long Island PFAS complex contribute to East Setauket's elevated readings.
Geology & Source: East Setauket in Suffolk County draws from Suffolk County Water Authority on the Long Island Aquifer (north-central Suffolk County) — the aquifer is developed in Pleistocene glacial outwash and Cretaceous Magothy Formation (quartz sand) — New York Long Island Pleistocene-Cretaceous aquifer produces very hard water at 177 mg/L with TDS 473.5 mg/L in this Suffolk County New York community.