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Rialto Water Hardness & Quality Report (2026)

Water Hardness

48.5mg/L
Soft

2.8 grains per gallon

Source

mixed

pH Level

7.3

neutral = 7.0

Lead

0.003 mg/L

✓ Below action level

TDS

102.5 mg/L

Est. Daily Cost

$0.13

energy & soap waste

Source: USGS Water Quality Portal · Updated 2026

48.5mg/L as CaCO₃Soft

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 Rialto, your appliances are currently losing 6% efficiency due to mineral buildup.

ApplianceIn RialtoSoft Water CityEfficiency Loss
Kettle
8 yrs
8.5 yrs-6%
Washing Machine
11.8 yrs
12 yrs-2%
Water Heater
13.7 yrs
15 yrs-9%
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Regional Water Comparison

How Rialto compares to its nearest neighbours

CityHardnessPFAS (ppt)RiskSource
Rialto, California48.5 mg/L3.3 ppt🟢 Softmixed
Bloomington, California142 mg/L6 ppt🟠 Hardmixed
Colton, California82 mg/L4.2 ppt🟡 Moderately Hardmixed
Fontana, California123 mg/L5.4 ppt🟠 Hardmixed
San Bernardino, California166 mg/L6.7 ppt🟠 Hardmixed

National Benchmark

How Rialto compares to the USA average

BenchmarkHardnessAppliance Risk
Rialto48.5 mg/L🟢 None
USA National Avg150 mg/L🟠 Moderate
Badger Top Rated8.5 mg/L🟢 None

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What Makes Rialto's Water Unique?

Local geology and source profile

Source: MixedTDS: 102.5 mg/LpH: 7.3

Rialto, California, in the western San Bernardino Valley in San Bernardino County, receives its municipal water supply through the City of Rialto Municipal Utilities Division, sourcing from the Rialto–Colton Basin groundwater wells — an alluvial aquifer recharged by Cajon Creek and Santa Ana River spreading from the San Bernardino Mountains — and from the San Bernardino Valley Municipal Water District (SBVMWD) State Water Project import water delivered via the Inland Feeder pipeline and Rialto distribution connections. Water hardness measures 48.5 mg/L — classified as soft.

Rialto's very soft supply reflects the character of the Rialto–Colton Basin alluvial aquifer — recharged primarily by the San Bernardino Mountains. Cajon Creek and Santa Ana River headwaters originate in the San Bernardino Mountains — draining Precambrian Peninsular Ranges crystalline terrain (augen gneiss, migmatite) and Cretaceous San Bernardino Mountains granite and quartz monzonite — all calcium-poor crystalline rock. The Cajon Pass alluvial fan and Santa Ana River upper valley spread this soft mountain runoff into the Rialto–Colton Basin alluvial gravel, and the shallow aquifer residence time in sandy fan deposits limits carbonate equilibration. The SWP import fraction adds soft Sierra Nevada–Feather River water to the blend.

With hardness at 48.5 mg/L, Rialto residents enjoy very soft water with minimal scale challenges. Soap and shampoo lather well. Faucet aerators and showerheads rarely need descaling. Dishwashers produce clean glassware. City of Rialto Municipal Utilities consistently delivers water meeting all California SWRCB and EPA Safe Drinking Water Act requirements.

Geology & Source: Mixed supply from the Rialto–Colton groundwater basin and San Bernardino Valley Municipal Water District (SBVMWD) State Water Project imports via the City of Rialto Water Utility — the Cajon Creek–Santa Ana River alluvial basin recharged by San Bernardino Mountains Precambrian crystalline and Mesozoic granodiorite produces very soft supply at 48.5 mg/L in the western San Bernardino Valley.

Other California Water Reports

Frequently Asked Questions

Is Rialto's water safe to drink?
Yes. Rialto's water meets all federal safety standards. The hardness is 48.5 mg/L (Soft), which is safe to drink. High hardness affects appliances and taste, but poses no health risk.
Do I need a water softener in Rialto?
Rialto's water is soft at 48.5 mg/L. A water softener is generally not necessary, though a carbon filter can improve taste and remove any remaining chlorine.
How does Rialto compare to the USA average?
The USA national average is 150 mg/L. Rialto at 48.5 mg/L is 101 mg/L below the national average. The softest major city is Badger at just 8.5 mg/L.
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