Hard water in Fountain Valley, CA
Reported by City of Fountain Valley · September 2023
- CA typical
- 121 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
The water in Fountain Valley carries roughly 125 mg/L of dissolved calcium and magnesium, or 7.3 grains per gallon. That is hard water. The number comes from City of Fountain Valley, dated September 2023.
At 125 mg/L, Fountain Valley is close to the typical California figure of 121 mg/L. Of the 10 nearest cities we track, 3 have softer water and 7 have harder. The range nearby runs from 96 mg/L in Costa Mesa to 283 in Garden Grove.
What 125 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 125 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 × 7.3 gpg = 1,645 grains a day. A 24,000-grain unit regenerates about every 14 days.
EPA record for Fountain Valley's water system
No health-based violations since 2016
Serves about 56,747 people from surface water.
- Health-based
- 0
- Monitoring or reporting
- 2
- 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 Fountain Valley water hard?
Yes. It measures about 125 mg/L (7.3 grains per gallon), which the USGS classes as hard.
What is the water hardness in Fountain Valley in grains per gallon?
About 7.3 gpg. One grain per gallon equals 17.1 mg/L, so 125 mg/L divided by 17.1 gives 7.3.
What size water softener do I need in Fountain Valley?
For 3 people using 75 gallons each per day, 7.3 gpg works out to about 1,645 grains a day. A 24,000-grain softener covers that with a regeneration about every 14 days.
Has the Fountain Valley water system had EPA violations?
EPA records show no health-based violations for City of Fountain Valley since 2016. There were also 2 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Huntington Beach128 mg/LHard
- Westminster267 mg/LVery hard
- Costa Mesa96 mg/LModerately hard
- Santa Ana150 mg/LHard
- Garden Grove283 mg/LVery hard
- Stanton196 mg/LVery hard
- Orange117 mg/LModerately hard
- Seal Beach169 mg/LHard
- Newport Beach102 mg/LModerately hard
- Los Alamitos196 mg/LVery hard
Hardness data: TapWaterData US Water Hardness (utility report, September 8, 2023), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.