Hard water in Colton, CA
Reported by San Bernardino Valley WD · August 2025
- CA typical
- 121 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
Tap water in Colton has about 139 mg/L of hardness, which is 8.1 grains per gallon. On the USGS scale that counts as hard. The number comes from San Bernardino Valley WD, dated August 2025.
Colton sits 18 mg/L above the typical California figure of 121. None of the 10 nearest cities we track has harder water. The range nearby runs from 72 mg/L in Muscoy to 137 in Grand Terrace.
What 139 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 139 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 × 8.1 gpg = 1,825 grains a day. A 24,000-grain unit regenerates about every 13 days.
EPA record for Colton's water system
No health-based violations since 2016
Serves about 46,525 people from groundwater.
- Health-based
- 0
- Monitoring or reporting
- 1
- Open now
- 0
EPA lists Colton, City of as the system serving Colton. The hardness figure above comes from a different system's report, which TapWaterData uses for Colton.
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 Colton water hard?
Yes. It measures about 139 mg/L (8.1 grains per gallon), which the USGS classes as hard.
What is the water hardness in Colton in grains per gallon?
About 8.1 gpg. One grain per gallon equals 17.1 mg/L, so 139 mg/L divided by 17.1 gives 8.1.
What size water softener do I need in Colton?
For 3 people using 75 gallons each per day, 8.1 gpg works out to about 1,825 grains a day. A 24,000-grain softener covers that with a regeneration about every 13 days.
Has the Colton water system had EPA violations?
EPA records show no health-based violations for Colton, City of since 2016. There were also 1 monitoring or reporting violation, which are about late or missing tests and notices.
Nearby cities
- Grand Terrace137 mg/LHard
- Highgrove99 mg/LModerately hard
- Bloomington96 mg/LModerately hard
- Loma Linda99 mg/LModerately hard
- Rialto89 mg/LModerately hard
- San Bernardino79 mg/LModerately hard
- Muscoy72 mg/LModerately hard
- Fontana92 mg/LModerately hard
- Redlands111 mg/LModerately hard
- Jurupa Valley122 mg/LHard
Hardness data: TapWaterData US Water Hardness (utility report, August 4, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.