County · South Dakota
Day County, South Dakota: drinking water records
This overview covers 7 ZIP codes and 10 community water systems in Day 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 |
|---|---|---|---|---|---|
| Web Water Development Association SD4601089 | 20,750 | 120 | 0 | 0 | 2 ppb |
| Brown-Day-Marshall Rws SD4600882 | 5,673 | 60 | 0 | 0 | 2 ppb |
| Bristol SD4600067 | 288 | 0 | 0 | 3 | 1 ppb |
| Clark Rural Water System SD4600881 | 2,325 | 0 | 0 | 0 | 0 ppb |
| Webster SD4600360 | 1,728 | 0 | 0 | 0 | 3 ppb |
| Clark Rural Water-Kampeska SD4602277 | 602 | 0 | 0 | 0 | 4 ppb |
| Waubay SD4600357 | 473 | 0 | 0 | 0 | 3 ppb |
| Roslyn SD4600284 | 181 | 0 | 0 | 0 | 1 ppb |
| Pierpont SD4600241 | 129 | 0 | 0 | 0 | 4 ppb |
| Grenville SD4600146 | 48 | 0 | 0 | 0 | 1 ppb |
ZIP reports in Day 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.