Surface Water Treatment Rule (SWTR) violations in Montana
30 active public water systems in Montana had a Surface Water Treatment Rule (SWTR) violation in the past three years, 13 of them in the latest quarter of EPA's data. What Surface Water Treatment Rule (SWTR) is and why it matters.
Systems with a Surface Water Treatment Rule (SWTR) violation
Latest quarter first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Philipsburg Town of Philipsburg · Granite County |
1,360 | 2 | 1 | |
|
Worden Ballantine Yellowstone Ballantine, Worden · Yellowstone County |
800 | 4 | 2 | |
|
North Valley County Water and Sewer Dist St Marie · Valley County |
450 | 5 | 2 | |
|
Highwood Mobile Home Park Great Falls · Cascade County |
400 | 1 | 1 | |
|
Denton Town of Denton · Fergus County |
255 | 2 | 1 | |
|
Heart Butte School County |
250 | 5 | 4 | |
|
Wilsall Water District Wilsall · Park County |
250 | 1 | 1 | |
|
Carter Chouteau CO Water Dist Carter · Chouteau County |
150 | 2 | 0 | |
|
Ncmrwa North Havre Cwd Leg Havre · Hill County |
90 | 2 | 0 | |
|
North Havre County Water Dist Havre · Hill County |
90 | 1 | 0 | |
|
Twin Hills Colony INC Carter · Chouteau County |
78 | 3 | 0 | |
|
Elkhorn Ranch Gallatin Gateway · Gallatin County |
65 | 4 | 2 | |
|
Essex County Water and or Sewer District Essex · Flathead County |
52 | 1 | 1 | |
|
Havre City of Havre · Hill County |
9,921 | 5 | 0 | |
|
Miles City City of Miles City · Custer County |
9,565 | 2 | 0 | |
|
Poplar, City of County |
3,025 | 5 | 2 | |
|
Ronan City of Ronan · Lake County |
2,483 | 3 | 0 | |
|
Colstrip City of Colstrip · Rosebud County |
2,350 | 2 | 0 | |
|
Blackfeet Community Hospital County |
600 | 3 | 1 | |
|
Fort Harrison Military Complex Fort Harrison · Lewis and Clark County |
580 | 1 | 0 | |
|
Snowbowl Lodge Missoula · Missoula County |
521 | 2 | 0 | |
|
Seville Water System County |
300 | 5 | 0 | |
|
Hysham Town of Hysham · Treasure County |
262 | 4 | 0 | |
|
Golden Sunlight Mines INC Whitehall · Jefferson County |
160 | 1 | 0 | |
|
Shade Tree Mobile Park Great Falls · Cascade County |
100 | 1 | 0 | |
|
Sweetgrass Water Users Assn Sweetgrass · Toole County |
100 | 3 | 1 | |
|
Missouri Meadows Community INC Great Falls · Cascade County |
85 | 1 | 0 | |
|
E Bar L Ranch Greenough · Missoula County |
84 | 2 | 0 | |
|
Hilldale Colony Havre · Hill County |
79 | 1 | 0 | |
|
Rivers Edge Mobile Home Park Grt Fls Great Falls · Cascade County |
75 | 1 | 0 |
About this data
A system is counted once if any of its violations in the past three years involved Surface Water Treatment Rule (SWTR), including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not Surface Water Treatment Rule (SWTR) 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.