County · Iowa
Winneshiek County, Iowa: drinking water records
This overview covers 7 ZIP codes and 13 community water systems in Winneshiek County. It also stands in for 0 ZIP codes whose utility has too little EPA data for a page of its own.
System population figures are summed from EPA registry records and can overlap where wholesalers and retail systems serve the same people. They are not a Census county-population estimate.
Water systems with the most complete records
| Water system | People served | PFAS survey results | PFAS found | Health-based violations | Lead, 9 in 10 homes at or below |
|---|---|---|---|---|---|
| Decorah Water Department IA9630012 | 7,615 | 360 | 1 | 0 | 9.4 ppb |
| Calmar Water Supply IA9615064 | 1,125 | 0 | 0 | 0 | 3.7 ppb |
| Ossian Water Supply IA9677007 | 802 | 0 | 0 | 0 | 5.1 ppb |
| Freeport Water District IA9630001 | 775 | 0 | 0 | 0 | 1.8 ppb |
| Spillville Water Supply IA9686077 | 371 | 0 | 0 | 0 | 5.8 ppb |
| Fort Atkinson Water Works IA9641049 | 347 | 0 | 0 | 0 | 2.5 ppb |
| Ridgeway, City of IA9680085 | 275 | 0 | 0 | 0 | 4.8 ppb |
| Castalia Water Works IA9620082 | 145 | 0 | 0 | 0 | 0.6 ppb |
| Frankville Rwd IA9644001 | 135 | 0 | 0 | 0 | 2 ppb |
| Scenic View Estates IA9630307 | 78 | 0 | 0 | 0 | 0.8 ppb |
| Sherman Place Water & Road, INC. IA9630303 | 73 | 0 | 0 | 0 | 4 ppb |
| Plantation Country View Subdivision IA9680301 | 32 | 0 | 0 | 0 | 7.9 ppb |
| Deerfield Heights Association IA9630316 | 28 | 0 | 0 | 0 | 5.2 ppb |
ZIP reports in Winneshiek County
No ZIP report in this county is published yet.
Sources and scope
EPA UCMR 5 occurrence data, samples collected 2023-01-03 – 2026-06-17, final release, August 2026 (file dated Aug 28, 2026); EPA SDWIS via ECHO, 2026Q2 extract (file dated Jul 9, 2026); EPA service-area boundaries v3.0; Census 2020 ZCTAs. Page generated 2026-09-03.
Counts cover the systems that report this county to EPA. A water system may cross county lines. "Found" means at least one result at or above the laboratory reporting level; it is not a compliance finding.