Hard water in Hermosa Beach, CA
Reported by California Water Service CO. - Herm/Redo · October 2025
- CA typical
- 121 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
The water in Hermosa Beach carries roughly 198 mg/L of dissolved calcium and magnesium, or 11.6 grains per gallon. That is very hard water. The number comes from California Water Service CO. - Herm/Redo, dated October 2025.
Hermosa Beach sits 77 mg/L above the typical California figure of 121. Of the 10 nearest cities we track, 8 have softer water and 1 has harder. The range nearby runs from 172 mg/L in El Segundo to 215 in Manhattan Beach.
What 198 mg/L means at home
Scale forms fast here. Kettles and coffee makers need regular descaling, and showerheads clog unless you clean them.
Tank water heaters collect mineral sediment that insulates the water from the burner, so flushing the tank matters more than usual.
Dishes and glass shower doors spot easily. Soap scum and a dull film on hair or laundry are common complaints.
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
At 198 mg/L most of the trouble is scale, and only a few things deal with it.
Ion-exchange water softener
The standard whole-house fix. It swaps calcium and magnesium for sodium or potassium and needs salt plus a drain. Size it with the calculator below.
Salt-free conditioner
No salt and no drain line. It changes how minerals form scale instead of removing them, so water still tests hard.
Reverse osmosis or carbon filter
Under-sink reverse osmosis removes minerals from drinking water only. Plain carbon filters improve taste but do not soften.
3 people × 75 gallons a day × 11.6 gpg = 2,606 grains a day. A 24,000-grain unit regenerates about every 9 days.
EPA record for Hermosa Beach's water system
No health-based violations since 2016
Serves about 100,072 people from surface water.
- Health-based
- 0
- Monitoring or reporting
- 0
- Open now
- 0
TapWaterData ties Hermosa Beach to this system. EPA's service-area records do not name Hermosa Beach, 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 Hermosa Beach water hard?
Yes. It measures about 198 mg/L (11.6 grains per gallon), which the USGS classes as very hard.
What is the water hardness in Hermosa Beach in grains per gallon?
About 11.6 gpg. One grain per gallon equals 17.1 mg/L, so 198 mg/L divided by 17.1 gives 11.6.
What size water softener do I need in Hermosa Beach?
For 3 people using 75 gallons each per day, 11.6 gpg works out to about 2,606 grains a day. A 24,000-grain softener covers that with a regeneration about every 9 days.
Has the Hermosa Beach water system had EPA violations?
EPA records show no health-based violations for California Water Service CO. - Herm/Redo since 2016.
Nearby cities
- Redondo Beach198 mg/LVery hard
- Manhattan Beach215 mg/LVery hard
- El Segundo172 mg/LHard
- Lawndale188 mg/LVery hard
- Del Aire185 mg/LVery hard
- Alondra Park185 mg/LVery hard
- Hawthorne189 mg/LVery hard
- Lennox185 mg/LVery hard
- Gardena185 mg/LVery hard
- Inglewood195 mg/LVery hard
Hardness data: TapWaterData US Water Hardness (utility report, October 2, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.