How hard is the water in Pittsburg, CA?

Tap water hardness
82mg/L
4.8gpg
Moderately hardReports range 82–96

Reported by Contra Costa Water District · October 2025

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

The water in Pittsburg carries roughly 82 mg/L of dissolved calcium and magnesium, or 4.8 grains per gallon. That is moderately hard water. The number comes from Contra Costa Water District, dated October 2025. Reports for this system disagree, with values from 82 to 96 mg/L.

Pittsburg on the hardness scale, with nearby cities
060120180240300360+CA typical 121Contra Costa Centre: 40 mg/LContra Costa Centre 40Pleasant Hill: 40 mg/LPleasant Hill 40Walnut Creek: 40 mg/LWalnut Creek 40Antioch: 82 mg/LAntioch 82Martinez: 84 mg/LMartinez 84Clayton: 86 mg/LClayton 86Concord: 86 mg/LConcord 86Brentwood: 86 mg/LBrentwood 86Bay Point: 88 mg/LBay Point 88Oakley: 89 mg/LOakley 89Pittsburg 82mg/L as calcium carbonate060120180240300360+CA 121Contra Costa Centre: 40 mg/LContra Cos. 40Pleasant Hill: 40 mg/LPleasant H. 40Antioch: 82 mg/LAntioch 82Clayton: 86 mg/LClayton 86Concord: 86 mg/LConcord 86Bay Point: 88 mg/LBay Point 8882 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 82 mg/L, Pittsburg is 39 mg/L below the typical California figure of 121. Of the 10 nearest cities we track, 3 have softer water and 6 have harder. The range nearby runs from 40 mg/L in Contra Costa Centre to 89 in Oakley.

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 Pittsburg

3 people × 75 gallons a day × 4.8 gpg = 1,082 grains a day. A 24,000-grain unit regenerates about every 22 days.

Size it for your household

EPA record for Pittsburg's water system

City of Pittsburg · PWSID CA0710008

No health-based violations since 2016

Serves about 62,500 people from surface water.

Health-based
0
Monitoring or reporting
0
Open now
0

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

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 Pittsburg 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 Pittsburg 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 Pittsburg?

For 3 people using 75 gallons each per day, 4.8 gpg works out to about 1,082 grains a day. A 24,000-grain softener covers that with a regeneration about every 22 days.

Has the Pittsburg water system had EPA violations?

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

Nearby cities

All 515 cities in California

Hardness data: TapWaterData US Water Hardness (utility report, October 1, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.