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

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

Riverside Water Hardness & Quality Report (2026)

Water Hardness

hard

~120–179 mg/L

Hard

estimated · not lab-verified

Source

mixed

pH Level

neutral = 7.0

Lead

0 mg/L

✓ Below action level

TDS

530 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 Riverside, your appliances are currently losing 20% efficiency due to mineral buildup.

Appliance	In Riverside	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 Riverside compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Riverside, California	≈ 120–179 mg/L	10 ppt	🟠 Hard	mixed
Rubidoux, California	≈ 120–179 mg/L	6.8 ppt	🟠 Hard	mixed
Woodcrest, California	≈ 120–179 mg/L	3 ppt	🟠 Hard	mixed
Pedley, California	≈ 120–179 mg/L	7.4 ppt	🟠 Hard	mixed
Glen Avon, California	≈ 120–179 mg/L	5.5 ppt	🟠 Hard	mixed

National Benchmark

How Riverside compares to the USA average

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

Local geology and source profile

Source: MixedTDS: 530 mg/LpH: 9

Riverside Public Utilities (RPU) serves the city of Riverside in Riverside County, California, providing drinking water to over 300,000 residents across approximately 70 square miles. The utility sources water from approximately 50 local groundwater wells blending supplies from the Chino and Riverside Basins, plus imported surface water via the Metropolitan Water District of Southern California. Key treatment facilities include the Riverside Water Quality Treatment Plant, which processes blended sources to meet standards. RPU conducts over 20,000 tests annually for more than 200 contaminants, ensuring compliance with state and federal regulations.

The primary watershed influencing Riverside's supply is the Santa Ana River watershed, with groundwater recharged from local runoff and Colorado River aqueduct imports. The region's geology features alluvial basins overlying Tertiary and Quaternary sedimentary formations, including limestone and dolomite-rich layers from ancient marine deposits from the Santa Ana Mountains and Perris Valley. These carbonate rock formations dissolve readily, imparting a hard character to the groundwater, while the semi-arid climate limits dilution — producing a mineralised supply with elevated calcium and magnesium. Imported surface waters provide partial blending but do not fully offset the geological influence.

Hard water in Riverside causes significant scale buildup in pipes, water heaters, dishwashers, and washing machines — heaters may fail 30–50% sooner without treatment. Faucet aerators and showerheads clog quickly, producing low flow and white deposits. Regular vinegar descaling, sediment filters, and biannual heater flushing are recommended. A water softener is strongly advised given the hard supply typical of the Inland Empire. RPU reports pH around 7.5–8.2; 90th percentile copper is 0.2 ppm, below the action level; fluoride averages 0.47 ppm; nitrate blends to 5.3 ppm, under the 10 ppm MCL. Treatment includes chloramination, corrosion control, and advanced filtration.

Geology & Source: Chino and Riverside Basins — Pleistocene alluvium over Tertiary limestone and dolomite-rich sedimentary strata from Santa Ana Mountains; semi-arid climate limits dilution — high calcium and magnesium yield hard supply

Hardness Varies Across Riverside — Find Your Area

City average is ≈ 120–179 mg/L. Individual ZIP areas differ.

* ZIP code estimates are derived from the city-wide measurement. Actual readings may vary slightly by neighbourhood.

ZIP Code	Neighbourhood	Hardness (mg/L)	Risk Level
92501	Downtown Riverside	≈ 148	🟠 Hard
92522	Central Riverside	≈ 148	🟠 Hard
92503	Northwest Riverside	≈ 150	🟠 Hard
92505	Northwest Riverside	≈ 150	🟠 Hard
92506	Central Riverside	≈ 150	🟠 Hard
92507	East Riverside	≈ 150	🟠 Hard
92508	East Riverside Hills	≈ 150	🟠 Hard
92515	Box Springs area	≈ 150	🟠 Hard
92516	Canyon Crest	≈ 150	🟠 Hard
92521	UCR area	≈ 150	🟠 Hard
92504	Northeast Riverside	≈ 152	🟠 Hard
92509	Jurupa Valley area	≈ 152	🟠 Hard

Other California Water Reports

Rubidoux

≈ 120–179 mg/L

🟠 Hard

Woodcrest

≈ 120–179 mg/L

🟠 Hard

Pedley

≈ 120–179 mg/L

🟠 Hard

Glen Avon

≈ 120–179 mg/L

🟠 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 Riverside's water safe to drink?

Yes. Riverside'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 Riverside?

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

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