Hard water in West Covina, CA
Reported by Suburban Water Systems-San Jose · September 2025
- CA typical
- 121 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
West Covina water measures 170 mg/L (10.0 gpg) of hardness, hard by USGS standards. The number comes from Suburban Water Systems-San Jose, dated September 2025. Reports for this system disagree, with values from 128 to 170 mg/L.
At 170 mg/L, West Covina is 49 mg/L above the typical California figure of 121. Of the 10 nearest cities we track, 6 have softer water and 4 have harder. The range nearby runs from 34 mg/L in Avocado Heights to 275 in Charter Oak.
What 170 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 170 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 × 10.0 gpg = 2,241 grains a day. A 24,000-grain unit regenerates about every 10 days.
EPA record for West Covina's water system
No health-based violations since 2016
Serves about 170,523 people from surface water.
- Health-based
- 0
- Monitoring or reporting
- 1
- Open now
- 0
TapWaterData ties West Covina to this system. EPA's service-area records do not name West Covina, so check the utility printed on your water bill.
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 West Covina water hard?
Yes. It measures about 170 mg/L (10.0 grains per gallon), which the USGS classes as hard.
What is the water hardness in West Covina in grains per gallon?
About 10.0 gpg. One grain per gallon equals 17.1 mg/L, so 170 mg/L divided by 17.1 gives 10.0.
What size water softener do I need in West Covina?
For 3 people using 75 gallons each per day, 10.0 gpg works out to about 2,241 grains a day. A 24,000-grain softener covers that with a regeneration about every 10 days.
Has the West Covina water system had EPA violations?
EPA records show no health-based violations for Suburban Water Systems-San Jose since 2016. There were also 1 monitoring or reporting violation, which are about late or missing tests and notices.
Nearby cities
- Valinda223 mg/LVery hard
- Covina167 mg/LHard
- South San Jose Hills208 mg/LVery hard
- Vincent112 mg/LModerately hard
- West Puente Valley109 mg/LModerately hard
- Walnut210 mg/LVery hard
- Citrus112 mg/LModerately hard
- Charter Oak275 mg/LVery hard
- Avocado Heights34 mg/LSoft
- Hacienda Heights117 mg/LModerately hard
Hardness data: TapWaterData US Water Hardness (utility report, September 29, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.