Colorado water quality by county
64 counties with public water systems. Pick a county to see every system that serves it.
| County | Active systems | People served | Share with violations, 3 yr | Serious violators | Health flags |
|---|---|---|---|---|---|
| Adams County | 89 | 713,420 | 2 | 4 | |
| Alamosa County | 17 | 16,356 | 0 | 1 | |
| Arapahoe County | 40 | 867,005 | 0 | 0 | |
| Archuleta County | 16 | 15,857 | 0 | 0 | |
| Baca County | 6 | 2,504 | 0 | 1 | |
| Bent County | 5 | 3,187 | 0 | 2 | |
| Boulder County | 80 | 436,911 | 1 | 4 | |
| Broomfield County | 3 | 108,783 | 0 | 0 | |
| Chaffee County | 73 | 25,957 | 1 | 3 | |
| Cheyenne County | 3 | 1,265 | 0 | 0 | |
| Clear Creek County | 34 | 28,923 | 0 | 1 | |
| Conejos County | 28 | 7,105 | 0 | 1 | |
| Costilla County | 12 | 2,872 | 0 | 1 | |
| Crowley County | 8 | 3,031 | 0 | 0 | |
| Custer County | 17 | 4,209 | 0 | 0 | |
| Delta County | 42 | 27,718 | 2 | 1 | |
| Denver County | 5 | 1,312,794 | 0 | 1 | |
| Dolores County | 6 | 1,420 | 0 | 0 | |
| Douglas County | 74 | 421,295 | 0 | 1 | |
| Eagle County | 47 | 103,406 | 1 | 0 | |
| El Paso County | 138 | 757,947 | 1 | 7 | |
| Elbert County | 28 | 15,735 | 0 | 2 | |
| Fremont County | 33 | 58,029 | 1 | 1 | |
| Garfield County | 85 | 60,229 | 1 | 1 | |
| Gilpin County | 20 | 22,489 | 0 | 0 | |
| Grand County | 80 | 56,251 | 0 | 1 | |
| Gunnison County | 74 | 28,235 | 0 | 0 | |
| Hinsdale County | 16 | 1,749 | 0 | 1 | |
| Huerfano County | 13 | 6,202 | 1 | 2 | |
| Jackson County | 13 | 2,234 | 0 | 0 | |
| Jefferson County | 113 | 577,913 | 0 | 1 | |
| Kiowa County | 4 | 889 | 0 | 0 | |
| Kit Carson County | 7 | 7,697 | 0 | 1 | |
| La Plata County | 114 | 63,149 | 1 | 2 | |
| Lake County | 22 | 12,406 | 2 | 2 | |
| Larimer County | 138 | 515,920 | 1 | 2 | |
| Las Animas County | 18 | 14,877 | 0 | 1 | |
| Lincoln County | 6 | 7,725 | 0 | 0 | |
| Logan County | 15 | 18,213 | 0 | 0 | |
| Mesa County | 36 | 164,223 | 0 | 0 | |
| Mineral County | 16 | 5,651 | 1 | 2 | |
| Moffat County | 17 | 11,845 | 1 | 2 | |
| Montezuma County | 18 | 31,851 | 1 | 2 | |
| Montrose County | 25 | 56,238 | 0 | 1 | |
| Morgan County | 8 | 28,903 | 0 | 1 | |
| Otero County | 23 | 19,329 | 2 | 12 | |
| Ouray County | 9 | 4,840 | 2 | 0 | |
| Park County | 77 | 12,707 | 2 | 5 | |
| Phillips County | 4 | 3,593 | 0 | 0 | |
| Pitkin County | 51 | 53,439 | 0 | 0 | |
| Prowers County | 10 | 11,670 | 1 | 3 | |
| Pueblo County | 27 | 167,528 | 3 | 3 | |
| Rio Blanco County | 11 | 5,746 | 0 | 0 | |
| Rio Grande County | 52 | 14,597 | 1 | 3 | |
| Routt County | 54 | 52,811 | 0 | 2 | |
| Saguache County | 17 | 6,738 | 0 | 1 | |
| San Juan County | 4 | 2,994 | 0 | 0 | |
| San Miguel County | 20 | 22,054 | 1 | 0 | |
| Sedgwick County | 4 | 1,794 | 0 | 0 | |
| Summit County | 43 | 89,779 | 0 | 1 | |
| Teller County | 51 | 23,730 | 1 | 8 | |
| Washington County | 6 | 3,731 | 0 | 0 | |
| Weld County | 79 | 362,521 | 0 | 3 | |
| Yuma County | 11 | 7,667 | 1 | 1 |
under 30% 30 to 59% 60% and over
About this data
Share with violations counts any violation in the past three years, including monitoring and reporting lapses. Counts cover active systems; systems serving more than one county are counted in each.
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. Retrieved from ECHO on Oct 11, 2026.