County · South Dakota
Clark County, South Dakota: drinking water records
This overview covers 6 ZIP codes and 8 community water systems in Clark 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 |
|---|---|---|---|---|---|
| Sioux Rural Water System SD4600866 | 4,280 | 120 | 0 | 1 | 4 ppb |
| Willow Lake SD4600370 | 255 | 0 | 0 | 1 | 1 ppb |
| Shamrock Colony SD4602267 | 75 | 0 | 0 | 1 | 1 ppb |
| Garden City SD4600137 | 33 | 0 | 0 | 5 | 1 ppb |
| Clark Rural Water System SD4600881 | 2,325 | 0 | 0 | 0 | 0 ppb |
| Clark SD4600091 | 1,148 | 0 | 0 | 0 | 4 ppb |
| Fordham Colony SD4602064 | 142 | 0 | 0 | 0 | 0 ppb |
| Collins Colony SD4602358 | 95 | 0 | 0 | 0 | 0 ppb |
ZIP reports in Clark 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.