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County Water Quality Report

Santa Clara County, California

11 public water systems serving 2,926,266 residents

Data sources: EPA SDWIS EPA ECHO EWG Tap Water Database Utility CCRs ⓘ How did we get these ratings?
County average grade
D
67/100
Utilities rated 11
Population served 2,926,266
Most recent test 2024

Top water quality concerns in Santa Clara County

  • Haloacetic acids (HAA5) significantly above health guidelinein 10 of 11 utilities
  • Haloacetic acids (HAA9) significantly above health guidelinein 7 of 11 utilities
  • Total trihalomethanes (TTHMs) significantly above health guidelinein 6 of 11 utilities
  • PFAS contaminationin 4 of 11 utilities
  • Perfluorohexane sulfonate (PFHXS) significantly above health guidelinein 4 of 11 utilities

All utilities in Santa Clara County

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

B
84/100

City of San Jose Water Department

San Jose · 1,027,000 residents

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

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B
80/100

CITY OF PALO ALTO

PALO ALTO · 67,231 residents

Top concern: Haloacetic acids (HAA9) significantly above health guideline

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B
78/100

GREAT OAKS WC INC

SAN JOSE · 110,088 residents

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

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C
73/100

CITY OF SANTA CLARA

SANTA CLARA · 130,746 residents

Top concern: Haloacetic acids (HAA9) significantly above health guideline

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C
72/100

CITY OF MILPITAS

MILPITAS · 81,773 residents

Top concern: Haloacetic acids (HAA9) significantly above health guideline

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C
70/100

CITY OF MOUNTAIN VIEW

MOUNTAIN VIEW · 81,501 residents

Top concern: Haloacetic acids (HAA9) significantly above health guideline

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C
66/100

CITY OF GILROY

GILROY · 59,203 residents

Top concern: PFAS contamination

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D
64/100

CITY OF SUNNYVALE

SUNNYVALE · 157,566 residents

Top concern: Haloacetic acids (HAA9) significantly above health guideline

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F
53/100

CWSC LOS ALTOS SUBURBAN

SAN JOSE · 69,973 residents

Top concern: PFAS contamination

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F
53/100

CITY OF SAN JOSE - EVG/EDV/COY

SAN JOSE · 101,265 residents

Top concern: PFAS contamination

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F
45/100

SAN JOSE WATER

SAN JOSE · 1,039,920 residents

Top concern: PFAS contamination

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