Hard water in El Segundo, CA
Reported by El Segundo-City, Water Dept. · 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 El Segundo carries roughly 172 mg/L of dissolved calcium and magnesium, or 10.1 grains per gallon. That is hard water. The number comes from El Segundo-City, Water Dept., dated September 2025.
At 172 mg/L, El Segundo is 51 mg/L above the typical California figure of 121. Of the 10 nearest cities we track, 1 has softer water and 9 have harder. The range nearby runs from 121 mg/L in Marina del Rey to 215 in Manhattan Beach.
What 172 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 172 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 × 10.1 gpg = 2,264 grains a day. A 24,000-grain unit regenerates about every 10 days.
EPA record for El Segundo's water system
No health-based violations since 2016
Serves about 16,777 people from surface water.
- Health-based
- 0
- Monitoring or reporting
- 1
- 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 El Segundo water hard?
Yes. It measures about 172 mg/L (10.1 grains per gallon), which the USGS classes as hard.
What is the water hardness in El Segundo in grains per gallon?
About 10.1 gpg. One grain per gallon equals 17.1 mg/L, so 172 mg/L divided by 17.1 gives 10.1.
What size water softener do I need in El Segundo?
For 3 people using 75 gallons each per day, 10.1 gpg works out to about 2,264 grains a day. A 24,000-grain softener covers that with a regeneration about every 10 days.
Has the El Segundo water system had EPA violations?
EPA records show no health-based violations for El Segundo-City, Water Dept. since 2016. There were also 1 monitoring or reporting violation, which are about late or missing tests and notices.
Nearby cities
- Manhattan Beach215 mg/LVery hard
- Hermosa Beach198 mg/LVery hard
- Del Aire185 mg/LVery hard
- Lennox185 mg/LVery hard
- Lawndale188 mg/LVery hard
- Hawthorne189 mg/LVery hard
- Redondo Beach198 mg/LVery hard
- Marina del Rey121 mg/LHard
- Alondra Park185 mg/LVery hard
- Inglewood195 mg/LVery hard
Hardness data: TapWaterData US Water Hardness (utility report, September 8, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.