Water quality by county
in Idaho
EPA sampled public water systems across Idaho for PFAS under its UCMR 5 programme. Of the 44 counties, 2 have a reading above a federal limit and 16 have not been sampled at all — which is not a clean result, only an absence of one. Each county below shows what was found, at what concentration, and at which utility.
| county | Population | Worst result | Compound |
|---|---|---|---|
| Ada County | 535,799 | 7.0× | PFOS · 28.2 ng/L |
| Elmore County | 29,729 | 1.0× | PFHxS · 10 ng/L |
| Adams County | 4,998 | not sampled | — |
| Bannock County | 91,010 | under the limit | — |
| Bear Lake County | 6,779 | not sampled | — |
| Benewah County | 10,529 | not sampled | — |
| Bingham County | 50,889 | under the limit | — |
| Blaine County | 25,261 | under the limit | — |
| Boise County | 8,581 | not sampled | — |
| Bonner County | 53,955 | under the limit | — |
| Bonneville County | 133,644 | under the limit | — |
| Boundary County | 14,040 | not sampled | — |
| Butte County | 2,735 | not sampled | — |
| Camas County | 1,247 | not sampled | — |
| Canyon County | 266,892 | under the limit | — |
| Caribou County | 7,239 | not sampled | — |
| Cassia County | 25,976 | under the limit | — |
| Clark County | 794 | not sampled | — |
| Clearwater County | 9,151 | under the limit | — |
| Custer County | 4,597 | not sampled | — |
| Franklin County | 15,638 | under the limit | — |
| Fremont County | 14,399 | under the limit | — |
| Gem County | 21,857 | under the limit | — |
| Gooding County | 16,189 | under the limit | — |
| Idaho County | 17,912 | under the limit | — |
| Jefferson County | 34,854 | under the limit | — |
| Jerome County | 26,056 | under the limit | — |
| Kootenai County | 188,323 | under the limit | — |
| Latah County | 42,180 | under the limit | — |
| Lemhi County | 8,397 | not sampled | — |
| Lewis County | 3,728 | not sampled | — |
| Lincoln County | 5,556 | not sampled | — |
| Madison County | 55,549 | under the limit | — |
| Minidoka County | 22,691 | under the limit | — |
| Nez Perce County | 42,847 | under the limit | — |
| Oneida County | 4,976 | not sampled | — |
| Owyhee County | 12,748 | not sampled | — |
| Payette County | 27,662 | under the limit | — |
| Power County | 8,381 | under the limit | — |
| Shoshone County | 14,074 | under the limit | — |
| Teton County | 12,932 | not sampled | — |
| Twin Falls County | 96,509 | under the limit | — |
| Valley County | 12,777 | under the limit | — |
| Washington County | 11,539 | under the limit | — |