County Water Quality Report

St. Louis County, Missouri

2 public water systems serving 1,412,000 residents

Data sources: EPA SDWIS EPA ECHO EWG Tap Water Database Utility CCRs ⓘ How did we get these ratings?
County average grade
F
58/100
Utilities rated 2
Population served 1,412,000
Most recent test 2024
🇪🇺 Would fail EU standards 2 of 2

Top water quality concerns in St. Louis County

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

All utilities in St. Louis County

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

C
67/100

MO AMERICAN ST LOUIS ST CHARLES COUNTIES

CHESTERFIELD · 1,111,000 residents

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

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F
49/100

St. Louis Water Authority

St. Louis · 301,000 residents

Top concern: PFAS contamination

View report →