How does Monterey Park's water compare to the national average?

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

Monterey Park Water Hardness & Quality Report (2026)

Water Hardness

very hard

180+ mg/L

Very Hard

estimated · not lab-verified

Source

groundwater

pH Level

7.3

neutral = 7.0

Lead

0.002 mg/L

✓ Below action level

TDS

104 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 Monterey Park, your appliances are currently losing 45% efficiency due to mineral buildup.

Appliance	In Monterey Park	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 Monterey Park compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Monterey Park, California	≈ 180+ mg/L	19.6 ppt	🔴 Very Hard	groundwater
Alhambra, California	≈ 180+ mg/L	0 ppt	🔴 Very Hard	reservoir
San Gabriel, California	≈ 180+ mg/L	7.3 ppt	🔴 Very Hard	mixed
East San Gabriel, California	≈ 180+ mg/L	6.3 ppt	🔴 Very Hard	mixed
Rosemead, California	≈ 180+ mg/L	0 ppt	🔴 Very Hard	reservoir

National Benchmark

How Monterey Park compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Monterey Park	≈ 180+ mg/L	🔴 High
USA National Avg	151 mg/L	🟠 Moderate
Scarsdale Top Rated	0.02 mg/L	🟢 None

Bring Scarsdale-quality water to your Monterey Park home

Shop water softeners on Amazon.com →

Shop Now

What Makes Monterey Park's Water Unique?

Local geology and source profile

Source: GroundwaterTDS: 104 mg/LpH: 7.3

Monterey Park Water Department serves approximately 62,388 residents in Monterey Park, California, in Los Angeles County. The utility sources all its drinking water from production wells in the Main San Gabriel Groundwater Basin, situated outside city limits. Additional supply is purchased from San Gabriel Valley Water Company (SGVWC), which also extracts groundwater from the same basin. Water is tested, disinfected with chlorine, and delivered through wellhead processing; groundwater source assessments were completed in 2002 and 2005 by SGVWC, and full reports are available at the Water Department at 320 W Newmark Ave.

The Main San Gabriel Groundwater Basin is the primary aquifer for Monterey Park, located within the San Gabriel Valley. This basin features ancient limestone and sedimentary rock formations through which groundwater flows slowly over decades, dissolving substantial calcium carbonate, magnesium sulfate, and other mineral deposits from the geologic structure. These layers impart a very hard character to the supply due to natural mineral dissolution, alongside elevated total dissolved solids from the mineral-rich subsurface, producing a consistently mineralised profile shaped by regional geology.

Very hard water promotes significant scale buildup in pipes, heaters, and fixtures, reducing efficiency and lifespan. Water heaters, dishwashers, washing machines, and coffee makers are most affected, with mineral deposits accumulating rapidly and leading to higher energy bills and frequent repairs. Regular system flushing, installing scale inhibitors, and professional inspections are recommended maintenance steps; a water softener is strongly recommended for whole-home protection to improve soap efficiency and reduce skin dryness. The utility reports compliance with federal and state standards; notable detected contaminants include toluene, p-cresol, and five others above health guidelines, plus high TDS; aggregators note 12 detected contaminants in total.

Geology & Source: Main San Gabriel Groundwater Basin — ancient limestone and sedimentary rock formations; calcium carbonate and magnesium sulfate dissolve as groundwater percolates for decades, yielding a hard mineral-rich supply

Other California Water Reports

Alhambra

≈ 180+ mg/L

🔴 Very Hard

San Gabriel

≈ 180+ mg/L

🔴 Very Hard

East San Gabriel

≈ 180+ mg/L

🔴 Very Hard

Rosemead

≈ 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 Monterey Park's water safe to drink?

Yes. Monterey Park'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 Monterey Park?

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

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