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

The USA national average is 151 mg/L. Ossining (≈ 180+ mg/L) is 189 mg/L harder than average.

Ossining Water Hardness & Quality Report (2026)

Water Hardness

very hard

180+ mg/L

Very Hard

estimated · not lab-verified

Source

reservoir

pH Level

7.7

neutral = 7.0

Lead

0.004 mg/L

✓ Below action level

TDS

216.7 mg/L

Est. Daily Cost

$0.91

energy & soap waste

Source: See methodology section below · Updated 2026

very hard180+ mg/LVery Hard · 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 Ossining, your appliances are currently losing 45% efficiency due to mineral buildup.

Appliance	In Ossining	Soft Water City	Efficiency Loss
Kettle	4.7 yrs	8.5 yrs	-45%
Washing Machine	6.6 yrs	12 yrs	-45%
Water Heater	8.3 yrs	15 yrs	-45%

Regional Water Comparison

How Ossining compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Ossining, New York	≈ 180+ mg/L	4.3 ppt	🔴 Very Hard	reservoir
Sleepy Hollow, New York	≈ 120–179 mg/L	0 ppt	🟠 Hard	reservoir
Tarrytown, New York	≈ 0–60 mg/L	0 ppt	🟢 Soft	reservoir
Haverstraw, New York	≈ 120–179 mg/L	6.4 ppt	🟠 Hard	groundwater
Cortlandt Manor, New York	≈ 120–179 mg/L	0 ppt	🟠 Hard	reservoir

National Benchmark

How Ossining compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Ossining	≈ 180+ mg/L	🔴 High
USA National Avg	151 mg/L	🟠 Moderate
Scarsdale Top Rated	0.02 mg/L	🟢 None

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What Makes Ossining's Water Unique?

Local geology and source profile

Source: ReservoirTDS: 216.7 mg/LpH: 7.7

The Ossining Water Department serves approximately 30,000 residents in the Village and Town of Ossining, Westchester County, New York. Water is sourced from two surface reservoirs: the Indian Brook Reservoir at 25 Fowler Avenue and the Croton Reservoir, part of New York City's expansive Croton watershed system. Treatment occurs at the Indian Brook Treatment Plant, equipped with an on-site laboratory for process control. The utility operates from 101 Route 9A, Ossining, NY 10562, and provides 24/7 emergency support via (914) 941-4099.

The Croton Watershed spans over 375 square miles in southeastern New York, draining into the Hudson River. Underlying geology includes ancient Precambrian gneisses and schists of the Manhattan Prong, with localized Paleozoic limestones and dolostones that weather to release alkaline earth metals. This hard supply reflects mineral dissolution from fractured bedrock and glacial overburden, yielding moderately mineralised water with elevated calcium and magnesium. No groundwater aquifer is utilized; surface runoff and reservoir storage shape the water chemistry.

Very hard water in Ossining leads to significant scale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency and lifespan. Appliances like coffee makers and faucets show white deposits, while soap lathering is poor, increasing detergent use. Maintenance involves regular vinegar descaling, installing sediment filters, and flushing heaters annually. A water softener is strongly recommended to mitigate these effects and protect plumbing. Ossining's 2024 Annual Drinking Water Quality Report confirms no violations of EPA or New York State standards, with all contaminants below allowable levels and routine monitoring of pH, lead, and copper.

Geology & Source: Croton Watershed, Hudson River Valley; Precambrian Fordham Gneiss and Yonkers Complex metamorphic/igneous bedrock with glacial till and Paleozoic limestones and dolomitic marbles — calcium and magnesium dissolution imparts hard character

Other New York Water Reports

Sleepy Hollow

≈ 120–179 mg/L

🟠 Hard

Tarrytown

≈ 0–60 mg/L

🟢 Soft

Haverstraw

≈ 120–179 mg/L

🟠 Hard

Cortlandt Manor

≈ 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 Ossining's water safe to drink?

Yes. Ossining's water meets all federal safety standards. The hardness is ≈ 180+ mg/L (Very Hard), which is safe to drink. High hardness affects appliances and taste, but poses no health risk.

Do I need a water softener in Ossining?

At ≈ 180+ mg/L (Very Hard), Ossining'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 45%.

How does Ossining compare to the USA average?

The USA national average is 151 mg/L. Ossining (≈ 180+ mg/L) is 189 mg/L above the national average. The softest major city is Scarsdale at just 0.02 mg/L.

Data Sources & Methodology

Water quality data for Ossining 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.