Idaho water quality by county
44 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 |
|---|---|---|---|---|---|
| Ada County | 86 | 516,682 | 2 | 1 | |
| Adams County | 17 | 3,786 | 0 | 0 | |
| Bannock County | 49 | 83,300 | 3 | 1 | |
| Bear Lake County | 32 | 7,967 | 2 | 2 | |
| Benewah County | 15 | 7,074 | 0 | 0 | |
| Bingham County | 76 | 38,101 | 4 | 6 | |
| Blaine County | 46 | 24,047 | 1 | 2 | |
| Boise County | 56 | 7,406 | 2 | 1 | |
| Bonner County | 152 | 40,140 | 4 | 3 | |
| Bonneville County | 134 | 138,851 | 5 | 5 | |
| Boundary County | 21 | 11,704 | 2 | 1 | |
| Butte County | 16 | 7,137 | 0 | 0 | |
| Camas County | 9 | 811 | 1 | 1 | |
| Canyon County | 142 | 219,459 | 6 | 1 | |
| Caribou County | 16 | 6,159 | 0 | 0 | |
| Cassia County | 51 | 19,158 | 1 | 2 | |
| Clark County | 7 | 1,067 | 0 | 0 | |
| Clearwater County | 26 | 6,972 | 2 | 2 | |
| Custer County | 59 | 5,881 | 1 | 3 | |
| Elmore County | 46 | 26,926 | 5 | 3 | |
| Franklin County | 22 | 11,044 | 4 | 3 | |
| Fremont County | 92 | 15,183 | 7 | 9 | |
| Gem County | 33 | 9,731 | 0 | 0 | |
| Gooding County | 26 | 9,437 | 3 | 1 | |
| Idaho County | 55 | 10,042 | 1 | 0 | |
| Jefferson County | 62 | 19,529 | 2 | 2 | |
| Jerome County | 26 | 17,895 | 1 | 1 | |
| Kootenai County | 193 | 181,138 | 5 | 4 | |
| Latah County | 35 | 41,383 | 2 | 1 | |
| Lemhi County | 44 | 5,930 | 2 | 1 | |
| Lewis County | 6 | 2,976 | 1 | 2 | |
| Lincoln County | 5 | 2,684 | 0 | 0 | |
| Madison County | 33 | 50,546 | 1 | 1 | |
| Minidoka County | 28 | 15,130 | 1 | 1 | |
| Nez Perce County | 25 | 39,959 | 1 | 0 | |
| Oneida County | 10 | 2,980 | 1 | 1 | |
| Owyhee County | 25 | 7,280 | 1 | 0 | |
| Payette County | 19 | 20,117 | 1 | 0 | |
| Power County | 16 | 6,760 | 4 | 2 | |
| Shoshone County | 36 | 15,871 | 2 | 1 | |
| Teton County | 26 | 8,446 | 0 | 0 | |
| Twin Falls County | 56 | 76,266 | 7 | 3 | |
| Valley County | 61 | 12,598 | 2 | 2 | |
| Washington County | 16 | 6,963 | 0 | 0 |
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 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. Retrieved from ECHO on Oct 11, 2026.