Montana
Madison County drinking water quality
46 active public water systems serve 14,432 people in Madison County. 17 are compliant, 29 had at least one EPA violation in the past three years, 0 are designated serious violators, and 1 carries a health flag.
Needs attention
Community water systems
12 systems, largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Big Sky County Water and Sewer Dist 363 Big Sky |
4,132 | 1 | 0 | |
|
Virginia City Water Dept Virginia City |
1,500 | 3 | 0 | |
|
Ennis Town of Ennis |
1,400 | 1 | 0 | |
|
Sheridan Town of Sheridan |
632 | 5 | 0 | |
|
Andesite Ridge Water System Big Sky |
450 | 0 | 0 | |
|
Twin Bridges Town of Twin Bridges |
424 | 0 | 0 | |
|
MT Moonlight Basin Big Sky |
355 | 0 | 0 | |
|
Lower Pioneer Mountain Water System Big Sky |
350 | 0 | 0 | |
|
Valley Garden Golf Village HOA Ennis |
195 | 0 | 0 | |
|
Encampment Trail Big Sky |
100 | 0 | 0 | |
|
Spanish Peaks Mountain Club Big Sky |
40 | 0 | 0 | |
|
Lone View Ridge Water System Big Sky |
37 | 0 | 0 |
Non-community systems (34: schools, campgrounds, workplaces, restaurants)
These systems serve places people visit rather than homes.
Inactive systems (48, no longer operating or reporting)
Kept for the record and excluded from the county totals above. Browse inactive systems.
About this data
Totals cover active systems. Systems serving more than one county are counted in each county. EPA counts the rules a system was in violation of, not the individual violations; one rule can carry several.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The Montana records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.