Montana
Yellowstone County drinking water quality
118 active public water systems serve 170,080 people in Yellowstone County. 44 are compliant, 74 had at least one EPA violation in the past three years, 2 are designated serious violators, and 1 carries a health flag.
Needs attention
Community water systems
54 systems, largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Double Diamond Subdivision Arbor Hills Billings |
50 | 1 | 0 | |
|
Sartorie Legacy Homes Billings |
35 | 1 | 0 | |
|
Silver Creek Condominiums in Yellowstone Billings |
28 | 1 | 0 | |
|
McCann's Water Service LLC Billings |
25 | 1 | 0 |
Non-community systems (64: schools, campgrounds, workplaces, restaurants)
These systems serve places people visit rather than homes.
Inactive systems (178, 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.