How hard is the water in Riverside, CA?

Tap water hardness
112mg/L
6.5gpg
Moderately hard

Reported by Eastern Municipal WD · 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 Riverside has about 112 mg/L of hardness, which is 6.5 grains per gallon. On the USGS scale that counts as moderately hard. The number comes from Eastern Municipal WD, dated September 2025.

Riverside on the hardness scale, with nearby cities
060120180240300360+CA typical 121Bloomington: 96 mg/LBloomington 96Woodcrest: 99 mg/LWoodcrest 99Highgrove: 99 mg/LHighgrove 99Home Gardens: 99 mg/LHome Gardens 99Norco: 99 mg/LNorco 99Jurupa Valley: 122 mg/LJurupa Valley 122Mead Valley: 122 mg/LMead Valley 122Grand Terrace: 137 mg/LGrand Terrace 137Colton: 139 mg/LColton 139Lake Mathews: 140 mg/LLake Mathews 140Riverside 112mg/L as calcium carbonate060120180240300360+CA 121Woodcrest: 99 mg/LWoodcrest 99Highgrove: 99 mg/LHighgrove 99Home Gardens: 99 mg/LHome Garde. 99Jurupa Valley: 122 mg/LJurupa Val. 122Grand Terrace: 137 mg/LGrand Terr. 137Lake Mathews: 140 mg/LLake Mathe. 140112 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 112 mg/L, Riverside is close to the typical California figure of 121 mg/L. Of the 10 nearest cities we track, 5 have softer water and 5 have harder. The range nearby runs from 96 mg/L in Bloomington to 140 in Lake Mathews.

What 112 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 Riverside

3 people × 75 gallons a day × 6.5 gpg = 1,472 grains a day. A 24,000-grain unit regenerates about every 16 days.

Size it for your household

EPA record for Riverside'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

EPA lists Riverside, City of as the system serving Riverside. The hardness figure above comes from a different system's report, which TapWaterData uses for Riverside.

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 Riverside water hard?

Somewhat. It measures about 112 mg/L (6.5 grains per gallon), which the USGS classes as moderately hard.

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

About 6.5 gpg. One grain per gallon equals 17.1 mg/L, so 112 mg/L divided by 17.1 gives 6.5.

What size water softener do I need in Riverside?

For 3 people using 75 gallons each per day, 6.5 gpg works out to about 1,472 grains a day. A 24,000-grain softener covers that with a regeneration about every 16 days.

Has the Riverside 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.