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

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

Montclair Water Hardness & Quality Report (2026)

Water Hardness

hard

~120–179 mg/L

Hard

estimated · not lab-verified

Source

reservoir

pH Level

6.8

neutral = 7.0

Lead

0.003 mg/L

✓ Below action level

TDS

189 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 Montclair, your appliances are currently losing 20% efficiency due to mineral buildup.

Appliance	In Montclair	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 Montclair compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Montclair, Virginia	≈ 120–179 mg/L	5.8 ppt	🟠 Hard	reservoir
Dale City, Virginia	74 mg/L	4.6 ppt	🟡 Moderately Hard	reservoir
Cherry Hill, Virginia	≈ 120–179 mg/L	10.1 ppt	🟠 Hard	reservoir
Lake Ridge, Virginia	≈ 120–179 mg/L	5.3 ppt	🟠 Hard	reservoir
Lorton, Virginia	≈ 120–179 mg/L	4.8 ppt	🟠 Hard	reservoir

National Benchmark

How Montclair compares to the USA average

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

Local geology and source profile

Source: ReservoirTDS: 189 mg/LpH: 6.8

Montclair, Virginia, is served by the East Prince William County water system, operated through a partnership between Fairfax Water and the Prince William County Service Authority. The primary source is the Occoquan Reservoir, treated at Fairfax Water's Frederick P. Griffith Water Treatment Plant in Fairfax County. This system supplies drinking water to eastern Prince William County communities including Montclair, Woodbridge, Lake Ridge, Dale City, Dumfries, Occoquan, and Triangle, as well as portions of the Hoadly Road area. Raw water from the reservoir undergoes conventional treatment — coagulation, sedimentation, filtration, and disinfection — before distribution.

The Occoquan Reservoir is fed by the Occoquan River watershed, spanning Fairfax, Prince William, and Loudoun counties in the Piedmont region. Underlying geology features metamorphosed volcanic and sedimentary rocks from the late Proterozoic to Paleozoic, with soils derived from saprolite over gneiss and schist from the Grenville orogeny. Weathering of feldspars and ferromagnesian silicates releases alkaline earth metals, contributing to a moderately mineralised supply. Tributaries like Bull Run cross fractured bedrock with moderate carbonate influence from Fall Line limestone outcrops, adding to hardness without producing karstic extremes.

With moderately hard water, users may notice scale buildup in kettles, dishwashers, and water heaters, along with reduced soap lathering and occasional spotting on glassware. Washing machines and coffee makers are also affected, with mineral deposits shortening lifespan if not addressed. Regular vinegar descaling, scale-inhibiting filters, or detergent additives help mitigate effects; a water softener is often recommended for households with aesthetic concerns. Fairfax Water maintains compliance with EPA standards — pH typically 7.2–8.0, lead and copper controlled via orthophosphate addition; disinfection byproducts like chloroform are managed through granular activated carbon and chloramination, with ozone pre-oxidation, dual-media filtration, and UV disinfection backup.

Geology & Source: Occoquan Reservoir watershed — Piedmont Precambrian–Paleozoic gneiss, schist, and granitic intrusions from Grenville orogeny; feldspar and ferromagnesian silicate weathering with Fall Line carbonate influence yields moderate hardness

Other Virginia Water Reports

Dale City

74 mg/L

🟡 Moderately Hard

Cherry Hill

≈ 120–179 mg/L

🟠 Hard

Lake Ridge

≈ 120–179 mg/L

🟠 Hard

Lorton

≈ 120–179 mg/L

🟠 Hard

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Frequently Asked Questions

Is Montclair's water safe to drink?

Yes. Montclair'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 Montclair?

At ≈ 120–179 mg/L (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 20%.

How does Montclair compare to the USA average?

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