How hard is the water in Suisun City, CA?

Tap water hardness
107mg/L
6.3gpg
Moderately hardReports range 107–150

Reported by Suisun-Solano Water Authority · March 2023

CA typical
121 mg/L
EPA health violations since 2016
11
Softener for 3 people
24k grain
Data
Utility report

Suisun City water measures 107 mg/L (6.3 gpg) of hardness, moderately hard by USGS standards. The number comes from Suisun-Solano Water Authority, dated March 2023. Reports for this system disagree, with values from 107 to 150 mg/L.

Suisun City on the hardness scale, with nearby cities
060120180240300360+CA typical 121Rio Vista: 49 mg/LRio Vista 49Napa: 54 mg/LNapa 54Benicia: 56 mg/LBenicia 56American Canyon: 65 mg/LAmerican Canyon 65Vallejo: 82 mg/LVallejo 82Pittsburg: 82 mg/LPittsburg 82Bay Point: 88 mg/LBay Point 88Vacaville: 94 mg/LVacaville 94Fairfield: 109 mg/LFairfield 109Dixon: 152 mg/LDixon 152Suisun City 107mg/L as calcium carbonate060120180240300360+CA 121Napa: 54 mg/LNapa 54Benicia: 56 mg/LBenicia 56American Canyon: 65 mg/LAmerican C. 65Bay Point: 88 mg/LBay Point 88Vacaville: 94 mg/LVacaville 94Fairfield: 109 mg/LFairfield 109107 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

At 107 mg/L, Suisun City is 14 mg/L below the typical California figure of 121. Of the 10 nearest cities we track, 8 have softer water and 2 have harder. The range nearby runs from 49 mg/L in Rio Vista to 152 in Dixon.

What 107 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 Suisun City

3 people × 75 gallons a day × 6.3 gpg = 1,408 grains a day. A 24,000-grain unit regenerates about every 17 days.

Size it for your household

EPA record for Suisun City's water system

Suisun-Solano Water Authority · PWSID CA4810005

11 health-based violations since 2016

Serves about 29,105 people from surface water.

Health-based
11
Monitoring or reporting
1
Open now
2

TapWaterData ties Suisun City to this system. EPA's service-area records do not name Suisun City, so check the utility printed on your water bill.

20162017201820192020202120222023202420252026Lead and Copper RuleTotal trihalomethanes (TTHM)'16'18'20'22'24'26Lead and Copper RuleTotal trihalomethanes (TTHM)
Each dot is one health-based violation, placed at the start of its compliance period.
Contaminant or ruleViolationsPeriodStatus
Lead and Copper Rulecorrosion control and lead sampling120241 open
Total trihalomethanes (TTHM)a disinfection byproduct102023–2024Resolved

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 Suisun City water hard?

Somewhat. It measures about 107 mg/L (6.3 grains per gallon), which the USGS classes as moderately hard.

What is the water hardness in Suisun City in grains per gallon?

About 6.3 gpg. One grain per gallon equals 17.1 mg/L, so 107 mg/L divided by 17.1 gives 6.3.

What size water softener do I need in Suisun City?

For 3 people using 75 gallons each per day, 6.3 gpg works out to about 1,408 grains a day. A 24,000-grain softener covers that with a regeneration about every 17 days.

Has the Suisun City water system had EPA violations?

EPA records show 11 health-based violations for Suisun-Solano Water Authority since 2016, involving Lead and Copper Rule, Total trihalomethanes (TTHM). There were also 1 monitoring or reporting violation, which are about late or missing tests and notices.

Nearby cities

All 515 cities in California

Hardness data: TapWaterData US Water Hardness (utility report, March 16, 2023), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.