Terryville Water Hardness & Quality Report (2026)
Water Hardness
7.3 grains per gallon
Source
reservoir
pH Level
7.8
neutral = 7.0
Lead
0.005 mg/L
✓ Below action level
TDS
266.4 mg/L
Est. Daily Cost
$0.33
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 Terryville, your appliances are currently losing 17% efficiency due to mineral buildup.
| Appliance | In Terryville | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 5.5 yrs | 8.5 yrs | -35% |
| Washing Machine | 9 yrs | 12 yrs | -25% |
| Water Heater | 10.6 yrs | 15 yrs | -29% |
Regional Water Comparison
How Terryville compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Terryville, New York | 125 mg/L | 6 ppt | 🟠 Hard | reservoir |
| Setauket-East Setauket, New York | 118 mg/L | 5.7 ppt | 🟡 Moderately Hard | reservoir |
| Selden, New York | 102 mg/L | 4.9 ppt | 🟡 Moderately Hard | reservoir |
| Mount Sinai, New York | 126.5 mg/L | 6.1 ppt | 🟠 Hard | reservoir |
| East Setauket, New York | 177 mg/L | 8.4 ppt | 🟠 Hard | reservoir |
National Benchmark
How Terryville compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Terryville | 125 mg/L | 🟠 Moderate |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Terryville's Water Unique?
Local geology and source profile
Terryville, New York, in Suffolk County — a Suffolk County hamlet adjacent to Port Jefferson Station and Coram in north-central Long Island — receives its water from the Suffolk County Water Authority, drawing from the Long Island aquifer system through the north-central Long Island distribution.
The moderately hard 125 mg/L hardness and TDS of 266.4 mg/L reflect the Suffolk County Long Island aquifer supply's moderate calcareous character — the Pleistocene Harbor Hill Moraine outwash sands contain calcareous shell fragments and glacial till, while the deeper Cretaceous Magothy aquifer is predominantly insoluble quartz sand (compare Port Jefferson Station NY: 122/260 in Suffolk County comparable; Coram NY: 128/272 in Suffolk County comparable; Terryville consistent moderate from the same Suffolk County Long Island Pleistocene aquifer supply). The Long Island aquifer at Suffolk County — Pleistocene Harbor Hill outwash (slightly calcareous — primary hardness contributor), Cretaceous Magothy aquifer (insoluble — dilutant), and Holocene surface recharge (slightly calcareous — minor TDS).
At 125 mg/L with TDS 266, Terryville's water is moderately hard — mild scale buildup in appliances over time. Semi-annual descaling is appropriate. The PFAS level of 6.0 ppt is elevated — a certified drinking water filter is recommended — the Suffolk County Long Island defense installations and industrial sources contribute to Terryville's elevated PFAS readings. Review the Suffolk County Water Authority's annual water quality report.
Geology & Source: Terryville in Suffolk County draws from the Suffolk County Water Authority on the Long Island aquifer (Suffolk County, south New York) — the Long Island aquifer at Suffolk County is developed in Pleistocene Harbor Hill outwash (slightly calcareous) and Cretaceous Magothy aquifer (insoluble) — New York Suffolk County Long Island Pleistocene supply produces moderately hard water at 125 mg/L with TDS 266.4 mg/L.