Sleepy Hollow Water Hardness & Quality Report (2026)

Water Hardness

hard

~120–179 mg/L

Hard

estimated · not lab-verified

Source

reservoir

pH Level

7.9

neutral = 7.0

Lead

0.006 mg/L

✓ Below action level

TDS

305 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 Sleepy Hollow, your appliances are currently losing 20% efficiency due to mineral buildup.

Appliance	In Sleepy Hollow	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 Sleepy Hollow compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Sleepy Hollow, New York	≈ 120–179 mg/L	0 ppt	🟠 Hard	reservoir
Tarrytown, New York	≈ 0–60 mg/L	0 ppt	🟢 Soft	reservoir
Greenburgh, New York	≈ 120–179 mg/L	0 ppt	🟠 Hard	reservoir
Dobbs Ferry, New York	≈ 120–179 mg/L	6.5 ppt	🟠 Hard	groundwater
Ossining, New York	≈ 180+ mg/L	4.3 ppt	🔴 Very Hard	reservoir

National Benchmark

How Sleepy Hollow compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Sleepy Hollow	≈ 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 Sleepy Hollow's Water Unique?

Local geology and source profile

Source: ReservoirTDS: 305 mg/LpH: 7.9

The Village of Sleepy Hollow, situated in Westchester County, New York, relies on New York City's municipal system for its water. This supply originates from surface water drawn via the Catskill or Delaware Aqueducts, feeding into the Kensico Reservoir located in Valhalla, New York. Before reaching Sleepy Hollow, the water undergoes preliminary treatment by New York City, including ultraviolet and chlorine disinfection, plus fluoride addition. The village’s water system operates continuously, drawing from this extensive regional infrastructure.

The Catskill watershed, which replenishes Sleepy Hollow's water source, is geologically defined by Devonian-age sedimentary rocks, primarily shales and sandstones. As water flows through these formations and soil, it naturally dissolves calcium and magnesium minerals. This process is what gives the water its characteristic hardness, a common trait in the Hudson Valley and lower New York regions, with mineral content often exceeding national averages.

Homeowners in Sleepy Hollow will likely notice the effects of hard water. It can make soaps and detergents less effective, leading to increased consumption and potentially duller laundry. You might also see mineral buildup, known as scale, forming inside pipes and appliances like water heaters, dishwashers, and washing machines, which can shorten their lifespan. To combat these issues and protect your home's plumbing and appliances from mineral deposits, installing a water softener is a good idea.

Geology & Source: Catskill region sedimentary rocks and shales; dissolved calcium and magnesium minerals from these formations create hardness

Other New York Water Reports

Tarrytown

≈ 0–60 mg/L

🟢 Soft

Greenburgh

≈ 120–179 mg/L

🟠 Hard

Dobbs Ferry

≈ 120–179 mg/L

🟠 Hard

Ossining

≈ 180+ mg/L

🔴 Very Hard

Report an Issue

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 Sleepy Hollow's water safe to drink?

Yes. Sleepy Hollow'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 Sleepy Hollow?

At ≈ 120–179 mg/L (Hard), Sleepy Hollow'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 Sleepy Hollow compare to the USA average?

The USA national average is 151 mg/L. Sleepy Hollow (≈ 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 Sleepy Hollow 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.