Water Hardness in 94806
San Pablo, California · Contra Costa County
Dataset updated March 9, 2026Matched to 8 water systemsTap readings can vary by utility zone, treatment, and plumbing. Methodology
How this ZIP reading is built
This ZIP reading is built from 8 matched water systems. When more than one system is matched, the displayed value is weighted toward larger known service populations when that data is available.
Hardness is a mineral-content reading, not a drinking-water safety rating. Use it for scale, appliance, and softener decisions; check your utility report or test your tap before sizing treatment equipment. See how we calculate local readings.
Water Systems Serving 94806
These are the systems matched to this ZIP code. The displayed ZIP value is weighted toward larger known service populations when population data is available.
| Water System | Source | Hardness | Pop. Served |
|---|---|---|---|
| Contra Costa Water District CA0710003 | surface water | 76 PPM Slightly HardUSGS estimate: 422 PPM | |
| City Of Antioch CA0710001 | surface water | 70 PPM Slightly HardUSGS estimate: 422 PPM | |
| Brentwood CA0710004 | surface water | 260 PPM Very Hard | |
| City Of Pittsburg CA0710008 | surface water | 56 PPM SoftUSGS estimate: 422 PPM | |
| Diablo Water District CA0710007 | surface water | 124 PPM Moderately HardUSGS estimate: 260 PPM |
Nearby Zip Codes
What This Means For You
Use this ZIP reading as a local planning estimate, not a final treatment specification. Hardness can vary by utility zone, seasonal blend, private well, and building plumbing. Confirm your tap reading with a utility report or home hardness test before sizing equipment.
Know your water hardness?
If you've tested your water or have your utility's CCR report, share your reading to help us improve accuracy for San Pablo, CA (94806).
Frequently Asked Questions
Is the water hard in San Pablo, CA (94806)?
The average water hardness in 94806 is 105 PPM (6.1 GPG), which is classified as slightly hard.
Do I need a water softener in 94806?
At 105 PPM, your water is relatively soft. A water softener is generally not necessary.
Is hard water in 94806 safe to drink?
Water hardness itself is a mineral-content reading, not a drinking-water safety rating. Calcium and magnesium are naturally occurring minerals, but you should check your utility's Consumer Confidence Report for contaminant and compliance information.
How many water systems serve 94806?
Zip code 94806 in San Pablo, California is served by 8 water systems.
Learn More About Your Water
How to Test Water Hardness at Home
Compare free lookups, soap tests, test strips, liquid drop kits, and lab tests for measuring water hardness.
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