City water profile
Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Fairfield, California.
Median indexed hardness
189PPM
3 indexed ZIPs
Range 186–192 PPM
City summary
Fairfield has 3 published ZIP profiles across Solano County. The indexed median is 189 PPM, compared with 189 PPM across California.
Among the 242 Californiacities with an indexed median, Fairfield ranks #124from highest to lowest. Across all 678 state ZIP profiles, available estimates run from 3.3to 728.5 PPM.
The 186–192 PPM range shows how much the available ZIP estimates vary within the city label.
Hardness distribution
3 of 3 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.
Evidence quality
Confidence labels
Observation window: Jan 13, 2016 to Jun 3, 2026.
ZIP directory
Open a ZIP for site-level provenance and measurements.
Public water systems
PWSID CA4810003
The system names this served city; Census place overlap links the city to this ZCTA.
Compliance history
1 unique active health-based record appears among associated systems. This does not mean every contaminant was tested at every tap.
| Record | System | Period | Status |
|---|---|---|---|
| LEAD AND COPPER RULE REVISIONS | CA4810003 | Oct 17, 2024 | Unaddressed |
| LEAD AND COPPER RULE REVISIONS | CA4810003 | Oct 17, 2024 | Unaddressed · health-based |
Practical next steps
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Questions people ask
The indexed city median is 189 PPM. Open the ZIP report to verify the distance and confidence behind that estimate.
Compliance history is utility-wide and cannot guarantee conditions at every tap. Check current notices and test when address-specific evidence is needed.
Choose treatment only after confirming the problem at the property. A softener targets hardness; contaminant treatment requires a matching, verified performance claim.