Water quality by county
in South Dakota
EPA sampled public water systems across South Dakota for PFAS under its UCMR 5 programme. Of the 66 counties, 1 have a reading above a federal limit and 14 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 |
|---|---|---|---|
| Pennington County | 115,979 | 2.6× | PFOS · 10.6 ng/L |
| Aurora County | 2,752 | not sampled | — |
| Beadle County | 19,459 | under the limit | — |
| Bennett County | 3,289 | not sampled | — |
| Bon Homme County | 7,071 | under the limit | — |
| Brookings County | 36,359 | under the limit | — |
| Brown County | 37,495 | under the limit | — |
| Brule County | 5,261 | not sampled | — |
| Buffalo County | 1,825 | not sampled | — |
| Butte County | 10,891 | under the limit | — |
| Campbell County | 1,342 | under the limit | — |
| Charles Mix County | 9,343 | under the limit | — |
| Clark County | 3,974 | under the limit | — |
| Clay County | 15,245 | under the limit | — |
| Codington County | 29,278 | under the limit | — |
| Corson County | 3,747 | not sampled | — |
| Custer County | 9,330 | not sampled | — |
| Davison County | 19,907 | under the limit | — |
| Day County | 5,408 | under the limit | — |
| Deuel County | 4,335 | under the limit | — |
| Dewey County | 5,322 | under the limit | — |
| Douglas County | 2,849 | under the limit | — |
| Edmunds County | 4,027 | under the limit | — |
| Fall River County | 7,359 | under the limit | — |
| Faulk County | 2,136 | under the limit | — |
| Grant County | 7,618 | under the limit | — |
| Gregory County | 4,110 | under the limit | — |
| Haakon County | 1,834 | under the limit | — |
| Hamlin County | 6,596 | under the limit | — |
| Hand County | 3,097 | under the limit | — |
| Hanson County | 3,477 | under the limit | — |
| Harding County | 1,325 | not sampled | — |
| Hughes County | 17,526 | under the limit | — |
| Hutchinson County | 7,416 | under the limit | — |
| Hyde County | 1,215 | under the limit | — |
| Jackson County | 2,737 | not sampled | — |
| Jerauld County | 1,689 | not sampled | — |
| Jones County | 874 | under the limit | — |
| Kingsbury County | 5,261 | not sampled | — |
| Lake County | 11,006 | under the limit | — |
| Lawrence County | 28,809 | under the limit | — |
| Lincoln County | 75,244 | under the limit | — |
| Lyman County | 3,721 | under the limit | — |
| Marshall County | 4,395 | under the limit | — |
| McCook County | 5,771 | under the limit | — |
| McPherson County | 2,307 | under the limit | — |
| Meade County | 30,918 | under the limit | — |
| Mellette County | 1,834 | under the limit | — |
| Miner County | 2,303 | not sampled | — |
| Minnehaha County | 208,639 | under the limit | — |
| Moody County | 6,529 | under the limit | — |
| Oglala Lakota County | 13,360 | not sampled | — |
| Perkins County | 2,832 | not sampled | — |
| Potter County | 2,402 | under the limit | — |
| Roberts County | 10,283 | under the limit | — |
| Sanborn County | 2,392 | not sampled | — |
| Spink County | 6,108 | under the limit | — |
| Stanley County | 3,015 | under the limit | — |
| Sully County | 1,468 | under the limit | — |
| Todd County | 9,172 | under the limit | — |
| Tripp County | 5,717 | under the limit | — |
| Turner County | 9,087 | under the limit | — |
| Union County | 17,402 | under the limit | — |
| Walworth County | 5,270 | under the limit | — |
| Yankton County | 23,509 | under the limit | — |
| Ziebach County | 2,418 | under the limit | — |