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

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

Montclair Water Hardness & Quality Report (2026)

Water Hardness

very hard

180+ mg/L

Very Hard

estimated · not lab-verified

Source

reservoir

pH Level

7.2

neutral = 7.0

Lead

0.001 mg/L

✓ Below action level

TDS

78.6 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 Montclair, your appliances are currently losing 45% efficiency due to mineral buildup.

Appliance	In Montclair	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 Montclair compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Montclair, California	≈ 180+ mg/L	85.5 ppt	🔴 Very Hard	reservoir
Claremont, California	≈ 180+ mg/L	7 ppt	🔴 Very Hard	reservoir
Ontario, California	≈ 120–179 mg/L	70.6 ppt	🟠 Hard	reservoir
Upland, California	≈ 120–179 mg/L	24.8 ppt	🟠 Hard	reservoir
Chino, California	≈ 120–179 mg/L	0 ppt	🟠 Hard	reservoir

National Benchmark

How Montclair compares to the USA average

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

Local geology and source profile

Source: ReservoirTDS: 78.6 mg/LpH: 7.2

Monte Vista Water District (MVWD) supplies drinking water to approximately 38,000 residents in Montclair and surrounding areas of San Bernardino County, California. The primary source is groundwater extracted from the San Gabriel Valley Groundwater Basin, accessed through district-operated wells. MVWD maintains treatment facilities to process this supply and publishes annual reports confirming compliance with state and federal drinking water standards, including the Lead and Copper Rule. No specific treatment plant names are detailed in available data, but disinfection and corrosion control are among the standard processes applied.

The San Gabriel Valley Basin is underlain by sedimentary rock formations including limestone aquifers and mineral-rich alluvial deposits from Pleistocene-era geological activity. Groundwater percolates through calcium carbonate-rich layers and magnesium sulfate-bearing rocks, dissolving substantial minerals along the way. The region's arid climate limits dilution and recharge, concentrating dissolved solids and producing a consistently hard supply. Total dissolved solids measure 607 ppm, reflecting the high mineral content shaped by this geology and the absence of diluting surface sources.

Very hard water in Montclair causes significant scale buildup in pipes, water heaters, dishwashers, and washing machines, potentially driving $1,380–1,880 in annual household damage through reduced efficiency and shortened appliance lifespan. Clogged fixtures, higher energy bills, soap inefficiency, and dry skin are common issues. Regular descaling and vinegar rinses are recommended; a whole-home water softener is strongly advised alongside point-of-use filters for comprehensive protection. MVWD reports full compliance with pH and lead/copper standards; notable concerns include Chromium (hexavalent), PFOA, and PFHPA detected above health advocacy guidelines in recent testing, though below legal limits — residents are advised to monitor emerging PFAS regulations.

Geology & Source: San Gabriel Valley Groundwater Basin; Pleistocene limestone, calcium carbonate layers, magnesium sulfate-bearing sedimentary rocks; arid climate concentrates dissolved solids — yields hard water

Other California Water Reports

Claremont

≈ 180+ mg/L

🔴 Very Hard

Ontario

≈ 120–179 mg/L

🟠 Hard

Upland

≈ 120–179 mg/L

🟠 Hard

Chino

≈ 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 Montclair's water safe to drink?

Yes. Montclair'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 Montclair?

At ≈ 180+ mg/L (Very Hard), Montclair'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 Montclair compare to the USA average?

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