Hard water in San Fernando, CA
Reported by Los Angeles-City, Dept. of Water & Power · October 2025
- CA typical
- 121 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
San Fernando water measures 121 mg/L (7.1 gpg) of hardness, hard by USGS standards. The number comes from Los Angeles-City, Dept. of Water & Power, dated October 2025. Reports for this system disagree, with values from 95 to 121 mg/L.
At 121 mg/L, San Fernando is close to the typical California figure of 121 mg/L. Of the 10 nearest cities we track, 4 have softer water and 4 have harder. The range nearby runs from 3 mg/L in La Crescenta-Montrose to 236 in Stevenson Ranch.
What 121 mg/L means at home
Expect white crust on faucets and showerheads, plus spots on dishes that come out of the dishwasher.
Kettles collect scale quickly. Water heaters build up sediment at the bottom of the tank, which makes them work harder over time.
Soap and detergent need a little more to lather, and soap scum shows up in the tub.
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 121 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 × 7.1 gpg = 1,593 grains a day. A 24,000-grain unit regenerates about every 15 days.
EPA record for San Fernando's water system
No health-based violations since 2016
Serves about 23,364 people from groundwater.
- Health-based
- 0
- Monitoring or reporting
- 0
- Open now
- 0
EPA lists San Fernando-City, Water Dept. as the system serving San Fernando. The hardness figure above comes from a different system's report, which TapWaterData uses for San Fernando.
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 San Fernando water hard?
Yes. It measures about 121 mg/L (7.1 grains per gallon), which the USGS classes as hard.
What is the water hardness in San Fernando in grains per gallon?
About 7.1 gpg. One grain per gallon equals 17.1 mg/L, so 121 mg/L divided by 17.1 gives 7.1.
What size water softener do I need in San Fernando?
For 3 people using 75 gallons each per day, 7.1 gpg works out to about 1,593 grains a day. A 24,000-grain softener covers that with a regeneration about every 15 days.
Has the San Fernando water system had EPA violations?
EPA records show no health-based violations for San Fernando-City, Water Dept. since 2016.
Nearby cities
- Burbank133 mg/LHard
- Stevenson Ranch236 mg/LVery hard
- La Crescenta-Montrose3 mg/LSoft
- Glendale86 mg/LModerately hard
- West Hollywood121 mg/LHard
- La Cañada Flintridge218 mg/LVery hard
- Beverly Hills121 mg/LHard
- Topanga77 mg/LModerately hard
- Calabasas77 mg/LModerately hard
- Castaic236 mg/LVery hard
Hardness data: TapWaterData US Water Hardness (utility report, October 6, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.