How hard is the water in Vallejo, CA?

Tap water hardness
82mg/L
4.8gpg
Moderately hard

Reported by City of Vallejo · September 2025

CA typical
121 mg/L
EPA health violations since 2016
0
Softener for 3 people
24k grain
Data
Utility report

Tap water in Vallejo has about 82 mg/L of hardness, which is 4.8 grains per gallon. On the USGS scale that counts as moderately hard. The number comes from City of Vallejo, dated September 2025.

Vallejo on the hardness scale, with nearby cities
060120180240300360+CA typical 121Rodeo: 34 mg/LRodeo 34Hercules: 34 mg/LHercules 34Pinole: 34 mg/LPinole 34San Pablo: 34 mg/LSan Pablo 34Richmond: 34 mg/LRichmond 34El Sobrante: 48 mg/LEl Sobrante 48El Cerrito: 51 mg/LEl Cerrito 51Benicia: 56 mg/LBenicia 56American Canyon: 65 mg/LAmerican Canyon 65Martinez: 84 mg/LMartinez 84Vallejo 82mg/L as calcium carbonate060120180240300360+CA 121Rodeo: 34 mg/LRodeo 34Hercules: 34 mg/LHercules 34Pinole: 34 mg/LPinole 34El Sobrante: 48 mg/LEl Sobrante 48Benicia: 56 mg/LBenicia 56American Canyon: 65 mg/LAmerican C. 6582 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Vallejo sits 39 mg/L below the typical California figure of 121. Of the 10 nearest cities we track, 9 have softer water and 1 has harder. The range nearby runs from 34 mg/L in Rodeo to 84 in Martinez.

What 82 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 Vallejo

3 people × 75 gallons a day × 4.8 gpg = 1,073 grains a day. A 24,000-grain unit regenerates about every 22 days.

Size it for your household

EPA record for Vallejo's water system

City of Vallejo · PWSID CA4810007

No health-based violations since 2016

Serves about 121,420 people from surface water.

Health-based
0
Monitoring or reporting
0
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 Vallejo water hard?

Somewhat. It measures about 82 mg/L (4.8 grains per gallon), which the USGS classes as moderately hard.

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

About 4.8 gpg. One grain per gallon equals 17.1 mg/L, so 82 mg/L divided by 17.1 gives 4.8.

What size water softener do I need in Vallejo?

For 3 people using 75 gallons each per day, 4.8 gpg works out to about 1,073 grains a day. A 24,000-grain softener covers that with a regeneration about every 22 days.

Has the Vallejo water system had EPA violations?

EPA records show no health-based violations for City of Vallejo since 2016.

Nearby cities

All 515 cities in California

Hardness data: TapWaterData US Water Hardness (utility report, September 7, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.