How hard is the water in San Bernardino, CA?

Tap water hardness
79mg/L
4.6gpg
Moderately hardReports range 79–100

Reported by San Bernardino City · August 2025

CA typical
121 mg/L
EPA health violations since 2016
0
Softener for 3 people
24k grain
Data
Utility report

The water in San Bernardino carries roughly 79 mg/L of dissolved calcium and magnesium, or 4.6 grains per gallon. That is moderately hard water. The number comes from San Bernardino City, dated August 2025. Reports for this system disagree, with values from 79 to 100 mg/L.

San Bernardino on the hardness scale, with nearby cities
060120180240300360+CA typical 121Crestline: 51 mg/LCrestline 51Muscoy: 72 mg/LMuscoy 72Rialto: 89 mg/LRialto 89Bloomington: 96 mg/LBloomington 96Loma Linda: 99 mg/LLoma Linda 99Highgrove: 99 mg/LHighgrove 99Redlands: 111 mg/LRedlands 111Highland: 123 mg/LHighland 123Grand Terrace: 137 mg/LGrand Terrace 137Colton: 139 mg/LColton 139San Bernardino 79mg/L as calcium carbonate060120180240300360+CA 121Muscoy: 72 mg/LMuscoy 72Rialto: 89 mg/LRialto 89Loma Linda: 99 mg/LLoma Linda 99Highland: 123 mg/LHighland 123Grand Terrace: 137 mg/LGrand Terr. 137Colton: 139 mg/LColton 13979 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

At 79 mg/L, San Bernardino is 42 mg/L below the typical California figure of 121. Of the 10 nearest cities we track, 2 have softer water and 8 have harder. The range nearby runs from 51 mg/L in Crestline to 139 in Colton.

What 79 mg/L means at home

You may see faint white spots on glasses and shower doors after the water dries.

Scale builds up slowly. A kettle or coffee maker needs descaling now and then, maybe every few months.

Hardness is not a health problem, and EPA sets no limit for it. It is a matter of scale and soap.

What to do about it

Optional. Plenty of households at this level live with it and descale the kettle now and then.

Water softener

Worth a look if spots on glass bother you, or if your tankless water heater manual asks for softer water.

Carbon filter

Improves taste and removes chlorine. It leaves calcium and magnesium in place.

Softener size for San Bernardino

3 people × 75 gallons a day × 4.6 gpg = 1,042 grains a day. A 24,000-grain unit regenerates about every 23 days.

Size it for your household

EPA record for San Bernardino's water system

San Bernardino City · PWSID CA3610039

No health-based violations since 2016

Serves about 214,665 people from groundwater.

Health-based
0
Monitoring or reporting
0
Open now
0

Health-based means a contaminant above its legal limit or a missed treatment step. Monitoring and reporting violations are late or missing tests and notices. Source: EPA ECHO, 2026Q3 export, violations with periods starting 2016 or later. Full EPA record.

Questions

Is San Bernardino water hard?

Somewhat. It measures about 79 mg/L (4.6 grains per gallon), which the USGS classes as moderately hard.

What is the water hardness in San Bernardino in grains per gallon?

About 4.6 gpg. One grain per gallon equals 17.1 mg/L, so 79 mg/L divided by 17.1 gives 4.6.

What size water softener do I need in San Bernardino?

For 3 people using 75 gallons each per day, 4.6 gpg works out to about 1,042 grains a day. A 24,000-grain softener covers that with a regeneration about every 23 days.

Has the San Bernardino water system had EPA violations?

EPA records show no health-based violations for San Bernardino City since 2016.

Nearby cities

All 515 cities in California

Hardness data: TapWaterData US Water Hardness (utility report, August 4, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.