Thallium violations in Montana
22 active public water systems in Montana had a Thallium violation in the past three years. What Thallium is and why it matters.
Health effects: Chronic thallium exposure causes hair loss, changes in blood chemistry, kidney damage, intestinal problems, and liver effects. It can also impair the nervous system. EPA has classified thallium as a possible human carcinogen (Group C). The very low MCL reflects its acute toxicity even at small doses.
Systems with a Thallium violation
Latest quarter first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Crow Agency Water System County |
2,057 | 7 | 2 | |
|
White Sulphur Springs City of White Sulphur Springs · Meagher County |
1,000 | 4 | 1 | |
|
Frenchtown High School Frenchtown · Missoula County |
550 | 5 | 0 | |
|
Box Elder School District 13g Box Elder · Hill County |
500 | 7 | 0 | |
|
Eagleman Community Water County |
400 | 3 | 0 | |
|
Paws UP Angus Ranch Main Complex Greenough · Missoula County |
327 | 3 | 0 | |
|
Clyde Park Water Dept Clyde Park · Park County |
300 | 6 | 0 | |
|
Wyola Water System County |
281 | 10 | 1 | |
|
Anderson School Bozeman · Gallatin County |
220 | 7 | 1 | |
|
Cskt Division of Fire Management County |
190 | 7 | 1 | |
|
Winnett Town of Winnett · Petroleum County |
187 | 8 | 1 | |
|
Cherry Creek Wua Glasgow Glasgow · Valley County |
180 | 5 | 0 | |
|
Bitterroot Gateway MB PK Lolo Lolo · Missoula County |
130 | 6 | 0 | |
|
Country Haven Estates Whispering Pines Columbus · Stillwater County |
100 | 4 | 0 | |
|
Greenfield Elem School Dist 75 Fairfield · Teton County |
90 | 5 | 0 | |
|
Swlo and Main Office Missoula · Missoula County |
75 | 7 | 0 | |
|
Hartland Colony Havre · Blaine County |
73 | 5 | 1 | |
|
Barnett Water Users System Helena · Lewis and Clark County |
70 | 6 | 0 | |
|
Water Resources Division Missoula · Missoula County |
60 | 8 | 1 | |
|
Houle Villa Water System County |
50 | 2 | 0 | |
|
Bolin Elementary School Dist 5 Terry · Prairie County |
45 | 5 | 0 | |
|
Fishermans Village Subdivision West Yellowstone · Gallatin County |
25 | 9 | 1 |
About this data
A system is counted once if any of its violations in the past three years involved Thallium, including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not Thallium alone.
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.