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

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

Harlem Water Hardness & Quality Report (2026)

Water Hardness

hard

~120–179 mg/L

Hard

estimated · not lab-verified

Source

reservoir

pH Level

7.8

neutral = 7.0

Lead

0.006 mg/L

✓ Below action level

TDS

262.2 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 Harlem, your appliances are currently losing 20% efficiency due to mineral buildup.

Appliance	In Harlem	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 Harlem compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Harlem, New York	≈ 120–179 mg/L	6 ppt	🟠 Hard	reservoir
East Harlem, New York	≈ 0–60 mg/L	5.2 ppt	🟢 Soft	reservoir
Morningside Heights, New York	≈ 120–179 mg/L	5.2 ppt	🟠 Hard	reservoir
Mott Haven, New York	≈ 0–60 mg/L	5.7 ppt	🟢 Soft	reservoir
Manhattan Valley, New York	≈ 0–60 mg/L	5.2 ppt	🟢 Soft	reservoir

National Benchmark

How Harlem compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Harlem	≈ 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 Harlem's Water Unique?

Local geology and source profile

Source: ReservoirTDS: 262.2 mg/LpH: 7.8

Harlem is served by the New York City Department of Environmental Protection (NYC DEP) water system (Public Water System ID NY7003493). The utility draws from three supplies: the Catskill/Delaware system (approximately 97% of Harlem's water), sourced from reservoirs and controlled lakes spanning Delaware, Greene, Schoharie, Sullivan, and Ulster counties; the Croton system (approximately 3%), originating in Putnam, Westchester, and Dutchess counties; and a groundwater supply in southeastern Queens. Water travels via aqueducts to treatment and distribution facilities serving Manhattan.

Harlem's water originates in the Catskill/Delaware and Croton watersheds, located 60–125 miles north in the Hudson Valley and Catskill Mountains. The Catskill/Delaware watershed — dominant at 97% of supply — is characterized by minimal limestone deposits and low mineral content, yielding soft to slightly hard water. The Croton watershed passes through more mineralized geological formations, contributing moderate hardness. The blended supply reflects the predominantly soft Catskill/Delaware character; citywide hardness averages approximately 1.8 grain/gallon (CaCO₃), though blended areas can reach 7 grain/gallon.

At moderate blended hardness, residents may notice reduced soap efficiency, mineral buildup on fixtures and appliances, and decreased performance in dishwashers and washing machines. Water softening is recommended for households using high-temperature appliances or concerned about scale in pipes and water heaters; regular appliance maintenance and periodic descaling mitigate wear. NYC DEP treats and monitors the supply to meet Safe Drinking Water Act standards; fluoride is not detected in Harlem's drinking water. Annual Consumer Confidence Reports are available via the NYC DEP website or 311.

Geology & Source: Catskill/Delaware watersheds (97%) — minimal limestone, low mineral content, soft to slightly hard; Croton watershed (3%) — moderately mineralized formations; blended supply reflects predominantly soft Catskill/Delaware character

Other New York Water Reports

East Harlem

≈ 0–60 mg/L

🟢 Soft

Morningside Heights

≈ 120–179 mg/L

🟠 Hard

Mott Haven

≈ 0–60 mg/L

🟢 Soft

Manhattan Valley

≈ 0–60 mg/L

🟢 Soft

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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 Harlem's water safe to drink?

Yes. Harlem'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 Harlem?

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

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