County · Montana
Madison County, Montana: drinking water records
This overview covers 12 ZIP codes and 13 community water systems in Madison County. It also stands in for 6 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 |
|---|---|---|---|---|---|
| Big Sky County Water and Sewer Dist 363 MT0002385 | 4,132 | 120 | 1 | 0 | 4.8 ppb |
| Virginia City Water Dept MT0000353 | 1,500 | 0 | 0 | 5 | 0 ppb |
| Lower Pioneer Mountain Water System MT0004462 | 350 | 0 | 0 | 1 | 1 ppb |
| Tall Timbers Mobile Home Park IN5229012 | 90 | 0 | 0 | 1 | 0 ppb |
| Ennis Town of MT0000208 | 1,400 | 0 | 0 | 0 | 1 ppb |
| Sheridan Town of MT0000329 | 632 | 0 | 0 | 0 | 2 ppb |
| Andesite Ridge Water System MT0004468 | 450 | 0 | 0 | 0 | 3 ppb |
| Twin Bridges Town of MT0000349 | 424 | 0 | 0 | 0 | 2 ppb |
| Mt Moonlight Basin MT0004023 | 355 | 0 | 0 | 0 | 0.3 ppb |
| Valley Garden Golf Village HOA MT0003597 | 195 | 0 | 0 | 0 | 0 ppb |
| Encampment Trail MT0004916 | 100 | 0 | 0 | 0 | 12 ppb |
| Spanish Peaks Mountain Club MT0004588 | 40 | 0 | 0 | 0 | 1.7 ppb |
| Lone View Ridge Water System MT0004470 | 37 | 0 | 0 | 0 | 1 ppb |
ZIP reports in Madison 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: 59710, 59720, 59735, 59740, 59747, 59751.
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.