WaterQ

City Water Quality Rankings in California

599 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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#289
Upland
County, CA
95 A
#290
Westminster
County, CA
95 A
#291
Yountville
County, CA
95 A
#292
Altadena
County, CA
94 A
#293
Atwater
County, CA
94 A
#294
Avalon
County, CA
94 A
#295
Avila Beach
County, CA
94 A
#296
Barstow
County, CA
94 A
#297
Beaumont
County, CA
94 A
#298
Blairsden
County, CA
94 A
#299
Buellton
County, CA
94 A
#300
Cerritos
County, CA
94 A
#301
China Lake
County, CA
94 A
#302
Corona
County, CA
94 A
#303
Cotati
County, CA
94 A
#304
Covina
County, CA
94 A
#305
Crestline
County, CA
94 A
#306
Davis
County, CA
94 A
#307
Durham
County, CA
94 A
#308
El Verano
County, CA
94 A
#309
Escalon
County, CA
94 A
#310
Firebaugh
County, CA
94 A
#311
Fontana
County, CA
94 A
#312
Guadalupe
County, CA
94 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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