How hard is the water in Norco, CA?

Tap water hardness

99mg/L

5.8gpg

Moderately hard

Reported by Riverside, City of · September 2025

CA typical: 121 mg/L
EPA health violations since 2016: 1
Softener for 3 people: 24k grain
Data: Utility report

The water in Norco carries roughly 99 mg/L of dissolved calcium and magnesium, or 5.8 grains per gallon. That is moderately hard water. The number comes from Riverside, City of, dated September 2025.

Norco on the hardness scale, with nearby cities

Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Norco sits 22 mg/L below the typical California figure of 121. Of the 10 nearest cities we track, 2 have softer water and 6 have harder. The range nearby runs from 81 mg/L in Chino Hills to 274 in Anaheim.

What 99 mg/L means at home

You may see faint white spots on glasses and shower doors after the water dries.

Scale builds up slowly. A kettle or coffee maker needs descaling now and then, maybe every few months.

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

Optional. Plenty of households at this level live with it and descale the kettle now and then.

Water softener

Worth a look if spots on glass bother you, or if your tankless water heater manual asks for softer water.

Carbon filter

Improves taste and removes chlorine. It leaves calcium and magnesium in place.

Softener size for Norco

3 people × 75 gallons a day × 5.8 gpg = 1,298 grains a day. A 24,000-grain unit regenerates about every 18 days.

Size it for your household

EPA record for Norco's water system

Norco, City of · PWSID CA3310025

1 health-based violation since 2016

Serves about 25,068 people from surface water.

Health-based: 1
Monitoring or reporting: 42
Open now: 0

EPA lists Norco, City of as the system serving Norco. The hardness figure above comes from a different system's report, which TapWaterData uses for Norco.

Each dot is one health-based violation, placed at the start of its compliance period.

Contaminant or rule	Violations	Period	Status
Total trihalomethanes (TTHM)a disinfection byproduct	1	2025	Resolved

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 Norco water hard?

Somewhat. It measures about 99 mg/L (5.8 grains per gallon), which the USGS classes as moderately hard.

What is the water hardness in Norco in grains per gallon?

About 5.8 gpg. One grain per gallon equals 17.1 mg/L, so 99 mg/L divided by 17.1 gives 5.8.

What size water softener do I need in Norco?

For 3 people using 75 gallons each per day, 5.8 gpg works out to about 1,298 grains a day. A 24,000-grain softener covers that with a regeneration about every 18 days.

Has the Norco water system had EPA violations?

EPA records show 1 health-based violation for Norco, City of since 2016, involving Total trihalomethanes (TTHM). There were also 42 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 515 cities in California

Hardness data: TapWaterData US Water Hardness (utility report, September 22, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.