City water profile
Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Modesto, California.
Median indexed hardness
257PPM
8 indexed ZIPs
Range 223–274 PPM
City summary
Modesto has 8 published ZIP profiles across Stanislaus County. The indexed median is 257 PPM, compared with 189 PPM across California.
Among the 242 Californiacities with an indexed median, Modesto ranks #46from highest to lowest. Across all 678 state ZIP profiles, available estimates run from 3.3to 728.5 PPM.
The 223–274 PPM range shows how much the available ZIP estimates vary within the city label.
Hardness distribution
8 of 8 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.
Evidence quality
Confidence labels
Observation window: Jan 12, 2016 to Jun 3, 2026.
ZIP directory
Open a ZIP for site-level provenance and measurements.
ZIP code
274 PPM
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ZIP code
257 PPM
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ZIP code
257 PPM
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ZIP code
264 PPM
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ZIP code
249 PPM
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ZIP code
257 PPM
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ZIP code
223 PPM
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ZIP code
274 PPM
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Public water systems
PWSID CA5010010
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CA5010005
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CA5010006
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CA5010029
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CA5010023
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CA5010033
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CA5010026
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CA5010031
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CA5010034
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CA5010035
The system names this served city; Census place overlap links the city to this ZCTA.
Compliance history
No active health-based violation appears among the associated systems in the represented EPA reporting quarter. This does not mean every contaminant was tested at every tap.
No violation records are included in the current lookback window.
Practical next steps
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Questions people ask
The indexed city median is 257 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.