St. Louis City, MO
drinking water quality
279,695 residents · 1 public water system
Worst PFAS result on federal record
No PFAS above the federal limit
EPA sampled 1 of 1 public water system here, together serving about 304,709 people. Last sampled 9/18/2024.
What this means
PFAS are industrial chemicals that EPA describes as breaking down only very slowly in the environment. In April 2024 EPA set the first enforceable national limits: 4 ng/L for PFOA and PFOS, 10 ng/L for PFHxS, PFNA and GenX.
These figures are county-level and come from EPA’s sampling of public water systems. They describe the worst result found in the county, not what comes out of any particular tap — that depends on which system serves the address, and on the plumbing in the building. A private well is not covered by this programme at all.