Rosemead, CA water hardness

Tap water hardness
46mg/L
2.7gpg
Soft

Reported by San Gabriel Valley Water CO.-El Monte · July 2025

CA typical
121 mg/L
EPA health violations since 2016
2
Data
Utility report

The water in Rosemead carries roughly 46 mg/L of dissolved calcium and magnesium, or 2.7 grains per gallon. That is soft water. The number comes from San Gabriel Valley Water CO.-El Monte, dated July 2025.

Rosemead on the hardness scale, with nearby cities
060120180240300360+CA typical 121South San Gabriel: 34 mg/LSouth San Gabriel 34South El Monte: 34 mg/LSouth El Monte 34El Monte: 48 mg/LEl Monte 48Temple City: 113 mg/LTemple City 113San Gabriel: 116 mg/LSan Gabriel 116San Marino: 116 mg/LSan Marino 116South Pasadena: 128 mg/LSouth Pasadena 128Alhambra: 137 mg/LAlhambra 137East San Gabriel: 192 mg/LEast San Gabriel 192East Pasadena: 192 mg/LEast Pasadena 192Rosemead 46mg/L as calcium carbonate060120180240300360+CA 121South San Gabriel: 34 mg/LSouth San. 34South El Monte: 34 mg/LSouth El M. 34El Monte: 48 mg/LEl Monte 48Temple City: 113 mg/LTemple City 113San Gabriel: 116 mg/LSan Gabriel 116Alhambra: 137 mg/LAlhambra 13746 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Rosemead sits 75 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 34 mg/L in South San Gabriel to 192 in East San Gabriel.

What 46 mg/L means at home

Soap and shampoo lather with very little product. Kettles and showerheads stay mostly free of white crust.

Some people notice that soap feels slow to rinse off in soft water. That slippery feel is normal and harmless.

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

Nothing, as far as hardness goes. At 46 mg/L a softener would have almost nothing to remove.

Carbon filter

If the water tastes of chlorine, a pitcher or faucet carbon filter takes care of that. It does not change hardness.

EPA record for Rosemead's water system

San Gabriel Valley Water CO.-El Monte · PWSID CA1910039

2 health-based violations since 2016

Serves about 240,000 people from groundwater.

Health-based
2
Monitoring or reporting
0
Open now
0

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

20162017201820192020202120222023202420252026Groundwater Rule'16'18'20'22'24'26Groundwater Rule
Each dot is one health-based violation, placed at the start of its compliance period.
Contaminant or ruleViolationsPeriodStatus
Groundwater Ruletreatment of well water22018–2019Resolved

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 Rosemead water hard?

No. It measures about 46 mg/L (2.7 grains per gallon), which the USGS classes as soft.

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

About 2.7 gpg. One grain per gallon equals 17.1 mg/L, so 46 mg/L divided by 17.1 gives 2.7.

Has the Rosemead water system had EPA violations?

EPA records show 2 health-based violations for San Gabriel Valley Water CO.-El Monte since 2016, involving Groundwater Rule.

Nearby cities

All 515 cities in California

Hardness data: TapWaterData US Water Hardness (utility report, July 21, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.