TTHM (Total Trihalomethanes) violations in Colorado
181 active public water systems in Colorado had a TTHM (Total Trihalomethanes) violation in the past three years, 13 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 |
|---|---|---|---|---|
|
Widefield Wsd El Paso County |
27,640 | 2 | 0 | |
|
Towaoc Water System County |
2,020 | 5 | 2 | |
|
Ralston Valley Wsd Jefferson County |
1,610 | 1 | 0 | |
|
Mancos Rural Water Company Montezuma County |
1,300 | 10 | 5 | |
|
Durango West MD NO 2 La Plata County |
930 | 2 | 1 | |
|
Williamsburg Town of Fremont County |
775 | 3 | 0 | |
|
Pinewood Springs WD Larimer County |
745 | 6 | 1 | |
|
Montezuma Cnty WD NO 1 Montezuma County |
490 | 5 | 2 | |
|
Florissant Wsd Teller County |
250 | 9 | 0 | |
|
Roundup River Ranch Eagle County |
167 | 3 | 1 | |
|
Ute Pass WA INC La Plata County |
120 | 6 | 1 | |
|
Valley Mobile Home LLC Alamosa County |
85 | 12 | 1 | |
|
Core Electric Cooperative Douglas County |
81 | 2 | 0 | |
|
US Department of the Army Fort Carson El Paso County |
48,000 | 1 | 0 | |
|
Pueblo West MD Pueblo County |
30,000 | 3 | 0 | |
|
Cherokee MD El Paso County |
29,610 | 1 | 0 | |
|
Csu Main and West Housing Campus Larimer County |
27,375 | 5 | 0 | |
|
MT Werner WD Routt County |
19,000 | 3 | 0 | |
|
Estes Park Town of Larimer County |
16,722 | 1 | 0 | |
|
Pinery Wwd Douglas County |
12,901 | 1 | 0 | |
|
Severance Town of Weld County |
11,733 | 2 | 0 | |
|
Wellington Town of Larimer County |
11,720 | 5 | 0 | |
|
Sterling Ranch Cab Douglas County |
11,501 | 2 | 0 | |
|
Trinidad City of Las Animas County |
11,400 | 2 | 0 | |
|
Cottonwood Wsd Douglas County |
10,867 | 7 | 0 | |
|
Rifle City of Garfield County |
9,489 | 2 | 0 | |
|
Milliken Town of Weld County |
9,200 | 2 | 0 | |
|
Silverthorne Town of Summit County |
8,400 | 2 | 0 | |
|
Vail Assoc Midvail Eagle Eagle County |
7,600 | 3 | 0 | |
|
Dacono City of Weld County |
6,900 | 1 | 0 | |
|
Stratmoor Hills Wsd El Paso County |
6,500 | 6 | 0 | |
|
Salida City of Chaffee County |
5,666 | 4 | 0 | |
|
Grand County Water NO 1 Grand County |
5,400 | 11 | 0 | |
|
Csu South Campus Fort Collins · Larimer County |
5,164 | 2 | 0 | |
|
Csu Foothills Campus Larimer County |
4,483 | 2 | 0 | |
|
Bennett Town of Adams County |
4,400 | 2 | 0 | |
|
Ault Town of Weld County |
4,220 | 2 | 0 | |
|
Battlement Mesa MD Garfield County |
4,100 | 6 | 0 | |
|
Hayden Town of Routt County |
3,982 | 4 | 0 | |
|
YMCA Rockies Wind River Larimer County |
3,730 | 7 | 2 | |
|
Dillon Town of Summit County |
3,254 | 1 | 0 | |
|
Colorado City MD Pueblo County |
2,755 | 8 | 4 | |
|
East Dillon WD Summit County |
2,501 | 3 | 0 | |
|
Wray City of Yuma County |
2,342 | 4 | 2 | |
|
LA Salle Town of Weld County |
2,010 | 4 | 1 | |
|
Creede City of Mineral County |
1,965 | 1 | 0 | |
|
Steamboat II MD Routt County |
1,450 | 8 | 1 | |
|
Foxridge Farms MHP Arapahoe County |
1,440 | 4 | 0 | |
|
Del Norte Town of Rio Grande County |
1,429 | 4 | 0 | |
|
Lookout Mountain WD Clear Creek County |
1,378 | 1 | 0 |
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 Colorado 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.