How hard is the water in Azusa, CA?

Tap water hardness
116mg/L
6.8gpg
Moderately hardReports range 72–116

Reported by Azusa Light and Water · September 2025

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

The water in Azusa carries roughly 116 mg/L of dissolved calcium and magnesium, or 6.8 grains per gallon. That is moderately hard water. The number comes from Azusa Light and Water, dated September 2025. Reports for this system disagree, with values from 72 to 116 mg/L.

Azusa on the hardness scale, with nearby cities
060120180240300360+CA typical 121Duarte: 75 mg/LDuarte 75South Monrovia Island: 75 mg/LSouth Monrovia Island 75Citrus: 112 mg/LCitrus 112Vincent: 112 mg/LVincent 112Glendora: 122 mg/LGlendora 122Monrovia: 135 mg/LMonrovia 135Mayflower Village: 135 mg/LMayflower Village 135Covina: 167 mg/LCovina 167West Covina: 170 mg/LWest Covina 170Charter Oak: 275 mg/LCharter Oak 275Azusa 116mg/L as calcium carbonate060120180240300360+CA 121Duarte: 75 mg/LDuarte 75Citrus: 112 mg/LCitrus 112Vincent: 112 mg/LVincent 112Glendora: 122 mg/LGlendora 122Covina: 167 mg/LCovina 167Charter Oak: 275 mg/LCharter Oak 275116 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Azusa sits close to the typical California figure of 121 mg/L. Of the 10 nearest cities we track, 4 have softer water and 6 have harder. The range nearby runs from 75 mg/L in Duarte to 275 in Charter Oak.

What 116 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 Azusa

3 people × 75 gallons a day × 6.8 gpg = 1,528 grains a day. A 24,000-grain unit regenerates about every 15 days.

Size it for your household

EPA record for Azusa's water system

Azusa Light and Water · PWSID CA1910007

No health-based violations since 2016

Serves about 110,044 people from surface water.

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 Azusa water hard?

Somewhat. It measures about 116 mg/L (6.8 grains per gallon), which the USGS classes as moderately hard.

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

About 6.8 gpg. One grain per gallon equals 17.1 mg/L, so 116 mg/L divided by 17.1 gives 6.8.

What size water softener do I need in Azusa?

For 3 people using 75 gallons each per day, 6.8 gpg works out to about 1,528 grains a day. A 24,000-grain softener covers that with a regeneration about every 15 days.

Has the Azusa water system had EPA violations?

EPA records show no health-based violations for Azusa Light and Water since 2016.

Nearby cities

All 515 cities in California

Hardness data: TapWaterData US Water Hardness (utility report, September 29, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.