Rowland Heights Water Hardness & Quality Report (2026)

Water Hardness

hard

~120–179 mg/L

Hard

estimated · not lab-verified

Source

reservoir

pH Level

8.1

neutral = 7.0

Lead

0.007 mg/L

✓ Below action level

TDS

489.7 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 Rowland Heights, your appliances are currently losing 20% efficiency due to mineral buildup.

Appliance	In Rowland Heights	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 Rowland Heights compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Rowland Heights, California	≈ 120–179 mg/L	22.7 ppt	🟠 Hard	reservoir
South San Jose Hills, California	≈ 180+ mg/L	3.6 ppt	🔴 Very Hard	mixed
Walnut, California	≈ 120–179 mg/L	0 ppt	🟠 Hard	reservoir
Brea, California	278 mg/L	0 ppt	🔴 Very Hard	reservoir
La Habra, California	≈ 180+ mg/L	0 ppt	🔴 Very Hard	reservoir

National Benchmark

How Rowland Heights compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Rowland Heights	≈ 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 Rowland Heights's Water Unique?

Local geology and source profile

Source: ReservoirTDS: 489.7 mg/LpH: 8.1

Rowland Water District serves approximately 62,303 residents in the Rowland Heights area of Los Angeles County, California. The utility sources its drinking water from purchased surface water, drawing supplies from regional surface water systems rather than local groundwater. The district's administrative headquarters is located at 3021 Fullerton Road, Rowland Heights, CA 91748 (phone: 562-697-1726). The utility is regulated by the California Department of Public Health (CDPH) and the U.S. Environmental Protection Agency (USEPA), operating under District 22 of the state's Division of Drinking Water.

Rowland Heights is situated over the Los Angeles Basin, dominated by Quaternary alluvial deposits overlying Tertiary sedimentary formations. The purchased surface water sources likely include supplies from the Los Angeles River watershed and imported water from the State Water Project, both of which originate in or pass through areas with significant calcium and magnesium-bearing mineral formations. This geological setting contributes to the characteristically hard water delivered to the district's customers.

Hard water in Rowland Heights causes mineral deposits to accumulate in water heaters, dishwashers, washing machines, and pipes, reducing efficiency and shortening equipment lifespan. Reduced soap lather, spotting on glassware, and buildup on fixtures are common. Water softening systems are widely recommended in the area to protect long-term plumbing infrastructure. The district's water quality report indicates a Langelier Saturation Index of approximately 4.2, with corrosivity indices ranging from 12.1 to 12.4, indicating moderately aggressive water chemistry. Potential contaminants identified include Di-n-butyl phthalate and Dibromomethane, though the utility maintains treatment and monitoring protocols to ensure compliance with maximum contaminant levels. Customers are advised to consult the annual Consumer Confidence Report available at rwd.org for full contaminant testing results.

Geology & Source: Los Angeles Basin — Quaternary alluvial deposits overlying Tertiary sedimentary formations with abundant calcium and magnesium-bearing minerals; imported surface water from Los Angeles River watershed and State Water Project passes through

Other California Water Reports

South San Jose Hills

≈ 180+ mg/L

🔴 Very Hard

Walnut

≈ 120–179 mg/L

🟠 Hard

Brea

278 mg/L

🔴 Very Hard

La Habra

≈ 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 Rowland Heights's water safe to drink?

Yes. Rowland Heights'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 Rowland Heights?

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

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