WaterQ

City Water Quality Rankings in California

601 cities ranked by drinking water quality.

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Popular city water quality comparisons

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Trending Cities

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#145
Twain Harte
County, CA
100 A
#146
Vernon
County, CA
100 A
#147
Waterford
County, CA
100 A
#148
Westwood
County, CA
100 A
#149
Wheatland
County, CA
100 A
#150
Whittier
County, CA
100 A
#151
Williams
County, CA
100 A
#152
Windsor
County, CA
100 A
#153
Winters
County, CA
100 A
#154
Yosemite Np
County, CA
100 A
#155
Yuba City
County, CA
100 A
#156
Atascadero
County, CA
99 A
#157
Auburn
County, CA
99 A
#158
Encinitas
County, CA
99 A
#159
Grass Valley
County, CA
99 A
#160
Idyllwild
County, CA
99 A
#161
Lost Hills
County, CA
99 A
#162
Oroville
County, CA
99 A
#163
Vallejo
County, CA
99 A
#164
Willits
County, CA
99 A
#165
Alhambra
County, CA
98 A
#166
Avila Beach
County, CA
98 A
#167
Baker
County, CA
98 A
#168
Baldwin Park
County, CA
98 A

Frequently Asked Questions

How are city water quality rankings calculated in California?

WaterQ city rankings are based on EPA SDWIS data across local public water systems, including contaminant detections, compliance violations, and recency-weighted score signals.

Can I compare two cities in California?

Yes. Use the city comparison links on this page or open the Compare tool to evaluate two cities side by side on score, grade, and water system coverage.

How often does WaterQ refresh city data?

City-level metrics refresh when new EPA data is processed. Check city pages for latest score and violation context.

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