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

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

Milpitas Water Hardness & Quality Report (2026)

Water Hardness

hard

~120–179 mg/L

Hard

estimated · not lab-verified

Source

reservoir

pH Level

neutral = 7.0

Lead

0.006 mg/L

✓ Below action level

TDS

394.8 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 Milpitas, your appliances are currently losing 20% efficiency due to mineral buildup.

Appliance	In Milpitas	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 Milpitas compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Milpitas, California	≈ 120–179 mg/L	0 ppt	🟠 Hard	reservoir
Santa Clara, California	≈ 120–179 mg/L	0 ppt	🟠 Hard	reservoir
San Jose, California	≈ 180+ mg/L	5.1 ppt	🔴 Very Hard	reservoir
Alum Rock, California	≈ 180+ mg/L	4.7 ppt	🔴 Very Hard	mixed
Sunnyvale, California	≈ 120–179 mg/L	0 ppt	🟠 Hard	reservoir

National Benchmark

How Milpitas compares to the USA average

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

Local geology and source profile

Source: ReservoirTDS: 394.8 mg/LpH: 8

The City of Milpitas Public Works Department manages the municipal water system serving approximately 80,000 residents in Milpitas, Santa Clara County, California. Water sources are mixed: the San Francisco Public Utilities Commission (SFPUC) delivers treated surface water from Hetch Hetchy Reservoir via the Sunol Valley Water Treatment Plant to areas including North San José/Alviso; the Santa Clara Valley Water District provides treated surface water from Anderson and Calero Reservoirs, Lake Del Valle, and San Luis Reservoir through the Santa Teresa Water Treatment Plant. Groundwater from the Santa Clara Valley Groundwater Basin supplements supplies in Edenvale and Coyote Valley service areas.

The primary watershed is Hetch Hetchy in the upper Tuolumne River basin, fed by Sierra Nevada snowmelt over granitic and metamorphic bedrock of Mesozoic age. Local reservoirs like Calero and Anderson capture runoff from Santa Clara County hills underlain by Franciscan mélange formations. The Santa Clara Valley Groundwater Basin, a key alluvial aquifer, consists of Quaternary river sediments filling a tectonic valley between the Santa Cruz Mountains and Diablo Range. Granite dissolution and alluvial mineral leaching impart a moderately mineralised character with natural calcium and magnesium, shaping the supply toward moderate hardness.

Moderately hard water promotes scale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency and lifespan while increasing energy costs. Dry skin, soap scum, and spotted dishes are common household effects. Regular descaling with vinegar, installing drain screens, and using high-efficiency appliances help mitigate issues. A water softener is recommended for homes with older plumbing to prevent gradual mineral accumulation. Milpitas water is safe and compliant per the annual Consumer Confidence Report from the City of Milpitas; treatment includes filtration, disinfection, and fluoridation at SFPUC and Santa Clara Valley plants. Copper and lead levels meet EPA action levels through corrosion control; chromium-6 and disinfection byproducts are monitored below MCLs.

Geology & Source: Sierra Nevada granitic and Mesozoic metavolcanic bedrock; Hetch Hetchy Reservoir via Tuolumne River; Santa Clara Valley Groundwater Basin Quaternary alluvial aquifer; Franciscan Complex influences — moderate hardness

Other California Water Reports

Santa Clara

≈ 120–179 mg/L

🟠 Hard

San Jose

≈ 180+ mg/L

🔴 Very Hard

Alum Rock

≈ 180+ mg/L

🔴 Very Hard

Sunnyvale

≈ 120–179 mg/L

🟠 Hard

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Frequently Asked Questions

Is Milpitas's water safe to drink?

Yes. Milpitas'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 Milpitas?

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

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