How hard is the water in Highgrove, CA?

Tap water hardness
99mg/L
5.8gpg
Moderately hard

Reported by Riverside, City of · September 2025

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

Tap water in Highgrove has about 99 mg/L of hardness, which is 5.8 grains per gallon. On the USGS scale that counts as moderately hard. The number comes from Riverside, City of, dated September 2025.

Highgrove on the hardness scale, with nearby cities
060120180240300360+CA typical 121San Bernardino: 79 mg/LSan Bernardino 79Rialto: 89 mg/LRialto 89Bloomington: 96 mg/LBloomington 96Loma Linda: 99 mg/LLoma Linda 99Redlands: 111 mg/LRedlands 111Riverside: 112 mg/LRiverside 112Moreno Valley: 122 mg/LMoreno Valley 122Jurupa Valley: 122 mg/LJurupa Valley 122Grand Terrace: 137 mg/LGrand Terrace 137Colton: 139 mg/LColton 139Highgrove 99mg/L as calcium carbonate060120180240300360+CA 121Bloomington: 96 mg/LBloomington 96Loma Linda: 99 mg/LLoma Linda 99Riverside: 112 mg/LRiverside 112Moreno Valley: 122 mg/LMoreno Val. 122Grand Terrace: 137 mg/LGrand Terr. 137Colton: 139 mg/LColton 13999 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 99 mg/L, Highgrove is 22 mg/L below the typical California figure of 121. Of the 10 nearest cities we track, 3 have softer water and 6 have harder. The range nearby runs from 79 mg/L in San Bernardino to 139 in Colton.

What 99 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 Highgrove

3 people × 75 gallons a day × 5.8 gpg = 1,303 grains a day. A 24,000-grain unit regenerates about every 18 days.

Size it for your household

EPA record for Highgrove's water system

Riverside, City of · PWSID CA3310031

No health-based violations since 2016

Serves about 302,776 people from surface water.

Health-based
0
Monitoring or reporting
0
Open now
0

TapWaterData ties Highgrove to this system. EPA's service-area records do not name Highgrove, so check the utility printed on your water bill.

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 Highgrove water hard?

Somewhat. It measures about 99 mg/L (5.8 grains per gallon), which the USGS classes as moderately hard.

What is the water hardness in Highgrove in grains per gallon?

About 5.8 gpg. One grain per gallon equals 17.1 mg/L, so 99 mg/L divided by 17.1 gives 5.8.

What size water softener do I need in Highgrove?

For 3 people using 75 gallons each per day, 5.8 gpg works out to about 1,303 grains a day. A 24,000-grain softener covers that with a regeneration about every 18 days.

Has the Highgrove water system had EPA violations?

EPA records show no health-based violations for Riverside, City of since 2016.

Nearby cities

All 515 cities in California

Hardness data: TapWaterData US Water Hardness (utility report, September 22, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.