County Water Quality Report

San Joaquin County, California

6 public water systems serving 929,377 residents

Data sources: EPA SDWIS EPA ECHO EWG Tap Water Database Utility CCRs ⓘ How did we get these ratings?
County average grade
F
53/100
Utilities rated 6
Population served 929,377
Most recent test 2024

Top water quality concerns in San Joaquin County

  • PFAS contaminationin 5 of 6 utilities
  • Arsenic significantly above health guidelinein 4 of 6 utilities
  • Haloacetic acids (HAA5) significantly above health guidelinein 4 of 6 utilities
  • Perfluorohexane sulfonate (PFHXS) significantly above health guidelinein 3 of 6 utilities
  • Haloacetic acids (HAA9) significantly above health guidelinein 3 of 6 utilities

All utilities in San Joaquin County

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

C
65/100

Stockton Water Authority

Stockton · 312,000 residents

Top concern: Lead detected in source water

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D
61/100

TRACY, CITY OF

TRACY · 96,609 residents

Top concern: PFAS contamination

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F
51/100

CITY OF STOCKTON

STOCKTON · 191,302 residents

Top concern: PFAS contamination

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F
48/100

CALIFORNIA WATER SERVICE - STOCKTON

SAN JOSE · 176,266 residents

Top concern: PFAS contamination

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F
47/100

LODI, CITY OF

LODI · 68,272 residents

Top concern: PFAS contamination

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F
47/100

MANTECA, CITY OF

MANTECA · 84,928 residents

Top concern: PFAS contamination

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