County · Montana
Fergus County, Montana: drinking water records
This overview covers 9 ZIP codes and 11 community water systems in Fergus County. It also stands in for 3 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 |
|---|---|---|---|---|---|
| Lewistown City of MT0000271 | 5,923 | 60 | 0 | 0 | 0 ppb |
| Winifred Town of MT0000363 | 274 | 0 | 0 | 1 | 1 ppb |
| Denton Town of MT0000199 | 255 | 0 | 0 | 75 | 4 ppb |
| King Ranch Colony MT0000432 | 56 | 0 | 0 | 23 | 0 ppb |
| Mountain Acres Mb Hm Pk MT0003809 | 320 | 0 | 0 | 0 | 0 ppb |
| Moore Town of MT0000295 | 186 | 0 | 0 | 0 | 0 ppb |
| Roy Water and Sewer District MT0002395 | 110 | 0 | 0 | 0 | 2 ppb |
| Grass Range Town of MT0000231 | 102 | 0 | 0 | 0 | 1 ppb |
| Ayers Hutterite Colony MT0000413 | 58 | 0 | 0 | 0 | 0 ppb |
| Deerfield Hutterite Colony MT0000431 | 51 | 0 | 0 | 0 | 0 ppb |
| Spring Creek Colony Lewistown MT0000433 | 48 | 0 | 0 | 0 | 0 ppb |
ZIP reports in Fergus County
No ZIP report in this county is published yet.
These ZIP codes are covered by this overview because their utility has too little EPA data for a separate page: 59424, 59441, 59451.
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.