County Water Quality Report

Sonoma County, California

2 public water systems serving 236,177 residents

Data sources: EPA SDWIS EPA ECHO EWG Tap Water Database Utility CCRs ⓘ How did we get these ratings?
County average grade
D
66/100
Utilities rated 2
Population served 236,177
🇪🇺 Would fail EU standards 1 of 2

Top water quality concerns in Sonoma County

  • Haloacetic acids (HAA5) significantly above health guidelinein 2 of 2 utilities
  • Total trihalomethanes (TTHMs) significantly above health guidelinein 2 of 2 utilities
  • Arsenic significantly above health guidelinein 1 of 2 utilities
  • Haloacetic acids (HAA9) significantly above health guidelinein 1 of 2 utilities

All utilities in Sonoma County

Click any utility for full grade card, contaminant data, and treatment plant contact info.

C
68/100

SANTA ROSA, CITY OF

SANTA ROSA · 175,396 residents

Top concern: Haloacetic acids (HAA5) significantly above health guideline

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D
63/100

PETALUMA, CITY OF

PETALUMA · 60,781 residents

Top concern: Arsenic significantly above health guideline

View report →