How hard is the water in Rosamond, CA?

Tap water hardness
103mg/L
6.0gpg
Moderately hardReports range 66–103

Reported by Rosamond CSD · 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 Rosamond carries roughly 103 mg/L of dissolved calcium and magnesium, or 6.0 grains per gallon. That is moderately hard water. The number comes from Rosamond CSD, dated September 2025. Reports for this system disagree, with values from 66 to 103 mg/L.

Rosamond on the hardness scale, with nearby cities
060120180240300360+CA typical 121La Crescenta-Montrose: 3 mg/LLa Crescenta-Montrose 3Palmdale: 62 mg/LPalmdale 62California City: 73 mg/LCalifornia City 73Lancaster: 80 mg/LLancaster 80San Fernando: 121 mg/LSan Fernando 121Bear Valley Springs: 158 mg/LBear Valley Springs 158Quartz Hill: 226 mg/LQuartz Hill 226Castaic: 236 mg/LCastaic 236Stevenson Ranch: 236 mg/LStevenson Ranch 236Tehachapi: 363 mg/LTehachapi 363Rosamond 103mg/L as calcium carbonate060120180240300360+CA 121Palmdale: 62 mg/LPalmdale 62California City: 73 mg/LCalifornia. 73Lancaster: 80 mg/LLancaster 80Bear Valley Springs: 158 mg/LBear Valle. 158Quartz Hill: 226 mg/LQuartz Hill 226Tehachapi: 363 mg/LTehachapi 363103 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Rosamond sits 18 mg/L below the typical California figure of 121. Of the 10 nearest cities we track, 4 have softer water and 6 have harder. The range nearby runs from 3 mg/L in La Crescenta-Montrose to 363 in Tehachapi.

What 103 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 Rosamond

3 people × 75 gallons a day × 6.0 gpg = 1,354 grains a day. A 24,000-grain unit regenerates about every 17 days.

Size it for your household

EPA record for Rosamond's water system

Rosamond CSD · PWSID CA1510018

No health-based violations since 2016

Serves about 18,150 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 Rosamond water hard?

Somewhat. It measures about 103 mg/L (6.0 grains per gallon), which the USGS classes as moderately hard.

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

About 6.0 gpg. One grain per gallon equals 17.1 mg/L, so 103 mg/L divided by 17.1 gives 6.0.

What size water softener do I need in Rosamond?

For 3 people using 75 gallons each per day, 6.0 gpg works out to about 1,354 grains a day. A 24,000-grain softener covers that with a regeneration about every 17 days.

Has the Rosamond water system had EPA violations?

EPA records show no health-based violations for Rosamond CSD since 2016.

Nearby cities

All 515 cities in California

Hardness data: TapWaterData US Water Hardness (utility report, September 30, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.