City Water Quality Rankings in California
599 cities ranked by drinking water quality.
Popular city water quality comparisons
Trending Cities
#97
Rialto
County, CA
100 A
#98 Ridgecrest
County, CA
100 A
#99 Rio Dell
County, CA
100 A
#100 Rio Vista
County, CA
100 A
#101 Ripon
County, CA
100 A
#102 Riverdale
County, CA
100 A
#103 Riverside
County, CA
100 A
#104 Rosamond
County, CA
100 A
#105 Royal Oaks
County, CA
100 A
#106 San Bruno
County, CA
100 A
#107 San Clemente
County, CA
100 A
#108 San Fernando
County, CA
100 A
#109 San Joaquin
County, CA
100 A
#110 San Miguel
County, CA
100 A
#111 Santa Clara
County, CA
100 A
#112 Santa Paula
County, CA
100 A
#113 Sausalito
County, CA
100 A
#114 Seal Beach
County, CA
100 A
#115 Seaside
County, CA
100 A
#116 Sebastopol
County, CA
100 A
#117 Shafter
County, CA
100 A
#118 Shasta
County, CA
100 A
#119 Shasta Lake
County, CA
100 A
#120 Skyforest
County, CA
100 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.