How does Terryville's water compare to the national average?

The USA national average is 151 mg/L. Terryville (≈ 120–179 mg/L) is 1 mg/L softer than average.

Terryville Water Hardness & Quality Report (2026)

Water Hardness

hard

~120–179 mg/L

Hard

estimated · not lab-verified

Source

reservoir

pH Level

5.7

neutral = 7.0

Lead

0.005 mg/L

✓ Below action level

TDS

203 mg/L

Est. Daily Cost

$0.40

energy & soap waste

Source: See methodology section below · Updated 2026

hard~120–179 mg/LHard · est.

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 20% efficiency due to mineral buildup.

Appliance	In Terryville	Soft Water City	Efficiency Loss
Kettle	6.8 yrs	8.5 yrs	-20%
Washing Machine	9.6 yrs	12 yrs	-20%
Water Heater	12 yrs	15 yrs	-20%

Regional Water Comparison

How Terryville compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Terryville, New York	≈ 120–179 mg/L	6 ppt	🟠 Hard	reservoir
Setauket-East Setauket, New York	≈ 0–60 mg/L	5.7 ppt	🟢 Soft	reservoir
Selden, New York	48 mg/L	4.9 ppt	🟢 Soft	reservoir
Mount Sinai, New York	≈ 120–179 mg/L	6.1 ppt	🟠 Hard	reservoir
East Setauket, New York	≈ 120–179 mg/L	8.4 ppt	🟠 Hard	reservoir

National Benchmark

How Terryville compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Terryville	≈ 120–179 mg/L	🟠 Moderate
USA National Avg	151 mg/L	🟠 Moderate
Scarsdale Top Rated	0.02 mg/L	🟢 None

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What Makes Terryville's Water Unique?

Local geology and source profile

Source: ReservoirTDS: 203 mg/LpH: 5.7

Unfortunately, specific water quality details for Terryville, New York, are not readily available. Public water quality databases, utility websites, and consumer confidence reports do not seem to list this location. To find the information you need, it might be helpful to verify the town's spelling or confirm the county. If Terryville is a smaller community, it's likely served by a larger water authority, such as a county water department or a regional service provider. Knowing that parent utility's name would allow for a more targeted search.

Terryville draws its water from the Long Island aquifer system in Suffolk County. This aquifer is geologically complex, with Pleistocene Harbor Hill outwash layers and the Cretaceous Magothy aquifer contributing to the water supply. The outwash deposits are described as slightly calcareous, while the Magothy aquifer is considered insoluble. These geological characteristics combine to yield water that is moderately hard.

While specific hardness levels aren't published, moderately hard water can lead to some buildup in pipes and appliances over time. You might notice this as scale deposits, especially in water heaters or dishwashers. Using less soap and detergent can help manage the effects. If you're concerned about the impact on your plumbing or appliances, a water softener could be a worthwhile consideration for your home.

Geology & Source: Long Island aquifer; Pleistocene outwash and Cretaceous Magothy aquifer produce moderately hard water

Other New York Water Reports

Setauket-East Setauket

≈ 0–60 mg/L

🟢 Soft

Selden

48 mg/L

🟢 Soft

Mount Sinai

≈ 120–179 mg/L

🟠 Hard

East Setauket

≈ 120–179 mg/L

🟠 Hard

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Notice an error or missing data? Help us keep this page accurate. If you spot incorrect water hardness, outdated utility info, or missing details, please let us know.

All reports are reviewed by our team. Thank you for supporting data quality!

Frequently Asked Questions

Is Terryville's water safe to drink?

Yes. Terryville's water meets all federal safety standards. The hardness is ≈ 120–179 mg/L (Hard), which is safe to drink. High hardness affects appliances and taste, but poses no health risk.

Do I need a water softener in Terryville?

At ≈ 120–179 mg/L (Hard), Terryville's water will cause significant limescale on kettles, washing machines, and water heaters. A water softener or descaler is strongly recommended to extend appliance lifespan and reduce energy bills by up to 20%.

How does Terryville compare to the USA average?

The USA national average is 151 mg/L. Terryville (≈ 120–179 mg/L) is 1 mg/L below the national average. The softest major city is Scarsdale at just 0.02 mg/L.

Data Sources & Methodology

Water quality data for Terryville is derived from geographic and geological modelling of the surrounding region. No federal monitoring station data was available for this location.

Estimated

Water Hardness

Modelled estimate based on state-level USGS geological survey data for this region. No direct USGS Water Quality Portal measurement was matched to this city — the value reflects a statistical range calibrated to the state's dominant rock types and typical source water characteristics.

Estimated

Estimated from regional geology and source water characteristics. pH is correlated with water hardness and local bedrock — values may differ from utility-reported figures.

Estimated

TDS — Total Dissolved Solids

Estimated using a derived ratio from water hardness and regional conductance profiles. TDS in natural water correlates strongly with total mineral content including hardness ions.

Measured

PFAS — Perfluoroalkyl and Polyfluoroalkyl Substances

EPA UCMR5 (5th Unregulated Contaminant Monitoring Rule, 2023–2025) — sum of PFAS compounds detected at the public water system serving this city. A value of 0 indicates the system was sampled with no detection above reporting limits.

Modelled

Lead

Modelled estimate based on the EPA Lead and Copper Rule 90th-percentile tap-sample methodology. No publicly available per-city lead dataset with sufficient national coverage exists. Values are a conservative baseline derived from city population tier and infrastructure age — all estimates are maintained below the EPA action level of 0.015 mg/L.

Calculated

Appliance Lifespan

Calculated from water hardness using a linear degradation model. Baseline lifespans represent soft-water performance (kettle: 8.5 yrs, washing machine: 12.0 yrs, water heater: 15.0 yrs). Hard water mineral scale progressively reduces operational life in direct proportion to hardness concentration.