Union County, SD
drinking water quality

17,402 residents · 10 public water systems · 6 ZIP codes

Worst PFAS result on federal record
No PFAS above the federal limit

EPA sampled 2 of 10 public water systems here, together serving about 10,030 people. Last sampled 9/3/2025.

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.

Request a test of your own supply.

This is Union County's worst federal result, not a reading from your tap. Leave a number and a local water specialist will test it.

No obligation. Your details go to a local water specialist to arrange the test, and to no one else.

ZIP codes in Union County

51001 · 51023 · 57001 · 57025 · 57038 · 57049

Readings are county-level, so every ZIP here shares the figure above. Search your ZIP on the map to see it in context.

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