Sioux County, IA
drinking water quality

36,554 residents · 16 public water systems · 14 ZIP codes

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

EPA sampled 5 of 16 public water systems here, together serving about 27,405 people. Last sampled 8/5/2025.

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 Sioux 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 Sioux County

51003 · 51011 · 51023 · 51027 · 51036 · 51041 · 51201 · 51234 · 51238 · 51239 · 51244 · 51247 · 51250 · 57034

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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