California Water Quality Reports

🔍Straight from EPA

🧪Real Lab Results

📅Updated Quarterly

🏠Local Expertise

Coverage right now: 58 counties fully profiled, 15795 water providers tracked.

Browse by county

Los Angeles County

601 water providers profiled

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Colusa County

67 water providers profiled

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Amador County

123 water providers profiled

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Santa Cruz County

193 water providers profiled

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Tulare County

713 water providers profiled

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El Dorado County

303 water providers profiled

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Merced County

237 water providers profiled

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Monterey County

672 water providers profiled

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Fresno County

704 water providers profiled

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Contra Costa County

179 water providers profiled

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Humboldt County

250 water providers profiled

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Lake County

291 water providers profiled

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Napa County

358 water providers profiled

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Plumas County

246 water providers profiled

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Sacramento County

467 water providers profiled

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Imperial County

136 water providers profiled

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Placer County

246 water providers profiled

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Kern County

682 water providers profiled

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Tuolumne County

274 water providers profiled

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San Luis Obispo County

252 water providers profiled

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San Joaquin County

571 water providers profiled

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Santa Clara County

320 water providers profiled

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San Bernardino County

669 water providers profiled

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Ventura County

179 water providers profiled

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San Benito County

149 water providers profiled

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Yolo County

218 water providers profiled

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San Diego County

414 water providers profiled

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Butte County

160 water providers profiled

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San Mateo County

113 water providers profiled

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Mariposa County

198 water providers profiled

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Tehama County

215 water providers profiled

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Siskiyou County

277 water providers profiled

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Sonoma County

756 water providers profiled

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Sutter County

218 water providers profiled

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Trinity County

231 water providers profiled

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Santa Barbara County

255 water providers profiled

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Calaveras County

97 water providers profiled

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Madera County

311 water providers profiled

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Solano County

186 water providers profiled

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Stanislaus County

442 water providers profiled

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Yuba County

120 water providers profiled

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Alpine County

57 water providers profiled

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Del Norte County

95 water providers profiled

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Sierra County

64 water providers profiled

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Mono County

127 water providers profiled

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Shasta County

401 water providers profiled

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Marin County

103 water providers profiled

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Riverside County

451 water providers profiled

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Alameda County

50 water providers profiled

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Orange County

167 water providers profiled

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Mendocino County

265 water providers profiled

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Nevada County

220 water providers profiled

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Modoc County

133 water providers profiled

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Kings County

99 water providers profiled

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Inyo County

175 water providers profiled

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Lassen County

152 water providers profiled

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Glenn County

107 water providers profiled

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San Francisco County

36 water providers profiled

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Learn more

What is TTHM? Understanding EPA Violation Status Is Chromium-6 Dangerous? Whole-House vs. Under-Sink Filtration Lead and Copper in Drinking Water What is PFAS? Arsenic and Uranium Explained Nitrate and Fluoride Explained Water Hardness, pH, and Turbidity What is Coliform Bacteria?