TTHM (Total Trihalomethanes) violations in Idaho
53 active public water systems in Idaho had a TTHM (Total Trihalomethanes) violation in the past three years, 1 of them in the latest quarter of EPA's data. What TTHM (Total Trihalomethanes) is and why it matters.
Systems with a TTHM (Total Trihalomethanes) violation
Latest quarter first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Bee Line Water Assn INC Boundary County |
533 | 2 | 0 | |
|
Moscow Water Dept Latah County |
26,000 | 1 | 0 | |
|
Rathdrum City of Kootenai County |
10,358 | 2 | 1 | |
|
Burley Water Dept Cassia County |
10,345 | 2 | 0 | |
|
Weiser City of Washington County |
5,630 | 1 | 0 | |
|
Preston City of Franklin County |
5,591 | 5 | 1 | |
|
Buhl City of Twin Falls County |
4,518 | 3 | 0 | |
|
McCall City of Valley County |
4,423 | 5 | 1 | |
|
Sun Valley Water and Sewer Dist Blaine County |
3,400 | 4 | 1 | |
|
Schweitzer Mountain Resort Bonner County |
3,301 | 4 | 0 | |
|
Salmon City of Lemhi County |
3,158 | 2 | 1 | |
|
Grangeville Water Dept Idaho County |
3,151 | 4 | 0 | |
|
Fort Hall Fort Hall · County |
2,850 | 8 | 2 | |
|
Bellevue City of Blaine County |
2,747 | 4 | 1 | |
|
Ashton City of Fremont County |
1,129 | 3 | 1 | |
|
Moyie Springs City of Boundary County |
1,123 | 1 | 0 | |
|
CS Beef Packing Ada County |
850 | 1 | 0 | |
|
Meadow Creek Property Owners Assn INC Adams County |
800 | 1 | 0 | |
|
Plummer Tribal Community Plummer · County |
515 | 2 | 0 | |
|
Terrace Lakes Water Company Boise County |
475 | 6 | 1 | |
|
Amalgamated Sugar Twin Falls Twin Falls County |
460 | 2 | 0 | |
|
Cave Bay Community System Kootenai County |
458 | 6 | 1 | |
|
Grand View, City of Owyhee County |
452 | 4 | 2 | |
|
Hecla Mining Company Lucky Friday Shoshone County |
420 | 1 | 0 | |
|
Northside Water Users Assn Bonner County |
413 | 1 | 0 | |
|
Bliss City of Gooding County |
384 | 2 | 0 | |
|
Culdesac City of Nez Perce County |
382 | 3 | 0 | |
|
Desmet Plummer · County |
355 | 2 | 0 | |
|
Unit 3 Water Assn Jerome County |
350 | 7 | 2 | |
|
Albion City of Cassia County |
325 | 3 | 2 | |
|
Elk City Water and Sewer Assn Idaho County |
320 | 5 | 0 | |
|
Colburn Water Assn Bonner County |
290 | 2 | 0 | |
|
Arrow Point Park Kootenai County |
275 | 1 | 0 | |
|
Royal Highland Water System Kootenai County |
275 | 2 | 1 | |
|
McCain Foods Cassia County |
267 | 3 | 0 | |
|
Twenty Mile Creek Water Assn Boundary County |
225 | 1 | 0 | |
|
Woodland Shores Water and Sewer Assn Kootenai County |
210 | 3 | 0 | |
|
Syringa Water and Sewer Kootenai County |
203 | 2 | 1 | |
|
Peck Water System Nez Perce County |
196 | 2 | 0 | |
|
Leisure Acres Trailer Court Shoshone County |
180 | 6 | 1 | |
|
Kidd Island Bay Water Users Kootenai County |
153 | 2 | 1 | |
|
Preston Eastside Water CO Franklin County |
120 | 10 | 3 | |
|
Country Court Community Idaho County |
89 | 4 | 0 | |
|
Town and Country Water Users Assn Elmore County |
86 | 4 | 2 | |
|
Ahsahka Water and Sewer Dist Clearwater County |
85 | 6 | 4 | |
|
Pleasant Acres Mobile Home Park Elmore County |
85 | 3 | 2 | |
|
Hoo Doo Harvard Water and Sewer Dist Latah County |
82 | 5 | 1 | |
|
Oden View Estates Improvement Assn Bonner County |
64 | 3 | 0 | |
|
Clear Lake Ranch P U D Gooding County |
54 | 6 | 2 | |
|
Pioneer Mobile Home Park LLC Homedale · Owyhee County |
53 | 4 | 1 |
About this data
A system is counted once if any of its violations in the past three years involved TTHM (Total Trihalomethanes), including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not TTHM (Total Trihalomethanes) 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 Idaho 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.