Water quality by county
in Missouri
EPA sampled public water systems across Missouri for PFAS under its UCMR 5 programme. Of the 115 counties, 9 have a reading above a federal limit and 24 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 |
|---|---|---|---|
| Pulaski County | 53,964 | 3.0× | PFOS · 12 ng/L |
| Camden County | 44,135 | 2.6× | PFOS · 10.3 ng/L |
| Phelps County | 45,672 | 2.5× | PFOS · 9.9 ng/L |
| Barton County | 11,717 | 1.6× | PFOA · 6.2 ng/L |
| Franklin County | 107,256 | 1.5× | PFOS · 5.9 ng/L |
| Cole County | 77,625 | 1.4× | PFOA · 5.8 ng/L |
| St. Charles County | 423,726 | 1.2× | PFOA · 4.9 ng/L |
| Greene County | 307,942 | 1.1× | PFOS · 4.3 ng/L |
| Ralls County | 10,499 | 1.1× | PFOA · 4.3 ng/L |
| Clay County | 263,370 | under the limit | PFHxS · 9.2 ng/L |
| Scott County | 37,957 | under the limit | PFHxS · 8 ng/L |
| Barry County | 35,618 | under the limit | PFHxS · 7.7 ng/L |
| St. Francois County | 67,503 | under the limit | PFHxS · 4.8 ng/L |
| Platte County | 113,207 | under the limit | PFHxS · 3.3 ng/L |
| Adair County | 25,660 | under the limit | — |
| Andrew County | 18,091 | under the limit | — |
| Atchison County | 5,139 | not sampled | — |
| Audrain County | 24,304 | under the limit | — |
| Bates County | 16,394 | under the limit | — |
| Benton County | 20,614 | under the limit | — |
| Bollinger County | 10,610 | not sampled | — |
| Boone County | 192,154 | under the limit | — |
| Buchanan County | 83,574 | under the limit | — |
| Butler County | 41,814 | under the limit | — |
| Caldwell County | 9,000 | under the limit | — |
| Callaway County | 45,126 | under the limit | — |
| Cape Girardeau County | 83,658 | under the limit | — |
| Carroll County | 8,414 | under the limit | — |
| Carter County | 5,359 | not sampled | — |
| Cass County | 113,873 | under the limit | — |
| Cedar County | 15,023 | under the limit | — |
| Chariton County | 7,397 | not sampled | — |
| Christian County | 96,045 | under the limit | — |
| Clark County | 6,623 | under the limit | — |
| Clinton County | 21,721 | under the limit | — |
| Cooper County | 17,122 | under the limit | — |
| Crawford County | 22,808 | under the limit | — |
| Dade County | 7,622 | under the limit | — |
| Dallas County | 17,877 | not sampled | — |
| Daviess County | 8,541 | under the limit | — |
| DeKalb County | 9,884 | under the limit | — |
| Dent County | 14,721 | under the limit | — |
| Douglas County | 12,290 | not sampled | — |
| Dunklin County | 27,002 | under the limit | — |
| Gasconade County | 14,655 | not sampled | — |
| Gentry County | 6,298 | not sampled | — |
| Grundy County | 9,766 | under the limit | — |
| Harrison County | 8,186 | under the limit | — |
| Henry County | 22,575 | under the limit | — |
| Hickory County | 8,766 | not sampled | — |
| Holt County | 4,241 | under the limit | — |
| Howard County | 10,150 | under the limit | — |
| Howell County | 40,762 | under the limit | — |
| Iron County | 9,420 | not sampled | — |
| Jackson County | 727,362 | under the limit | — |
| Jasper County | 126,479 | under the limit | — |
| Jefferson County | 231,888 | under the limit | — |
| Johnson County | 55,880 | under the limit | — |
| Knox County | 3,740 | under the limit | — |
| Laclede County | 36,738 | under the limit | — |
| Lafayette County | 33,511 | under the limit | — |
| Lawrence County | 39,151 | under the limit | — |
| Lewis County | 9,852 | not sampled | — |
| Lincoln County | 65,888 | under the limit | — |
| Linn County | 11,910 | under the limit | — |
| Livingston County | 14,658 | under the limit | — |
| Macon County | 15,177 | under the limit | — |
| Madison County | 12,852 | under the limit | — |
| Maries County | 8,506 | not sampled | — |
| Marion County | 28,425 | under the limit | — |
| McDonald County | 24,054 | under the limit | — |
| Mercer County | 3,452 | under the limit | — |
| Miller County | 25,668 | under the limit | — |
| Mississippi County | 11,750 | under the limit | — |
| Moniteau County | 15,294 | under the limit | — |
| Monroe County | 8,890 | under the limit | — |
| Montgomery County | 11,511 | under the limit | — |
| Morgan County | 22,399 | not sampled | — |
| New Madrid County | 15,212 | not sampled | — |
| Newton County | 61,519 | under the limit | — |
| Nodaway County | 20,503 | under the limit | — |
| Oregon County | 8,699 | not sampled | — |
| Osage County | 13,478 | not sampled | — |
| Ozark County | 9,090 | under the limit | — |
| Pemiscot County | 14,407 | under the limit | — |
| Perry County | 19,100 | under the limit | — |
| Pettis County | 43,791 | under the limit | — |
| Pike County | 17,961 | under the limit | — |
| Polk County | 33,070 | under the limit | — |
| Putnam County | 4,539 | not sampled | — |
| Randolph County | 24,077 | under the limit | — |
| Ray County | 23,199 | under the limit | — |
| Reynolds County | 5,927 | under the limit | — |
| Ripley County | 10,715 | not sampled | — |
| Saline County | 23,325 | under the limit | — |
| Schuyler County | 4,069 | under the limit | — |
| Scotland County | 4,698 | under the limit | — |
| Shannon County | 7,275 | not sampled | — |
| Shelby County | 5,926 | under the limit | — |
| St. Clair County | 9,848 | not sampled | — |
| St. Louis County | 279,695 | under the limit | — |
| St. Louis City | 279,695 | under the limit | — |
| Ste. Genevieve County | 18,546 | under the limit | — |
| Stoddard County | 28,438 | under the limit | — |
| Stone County | 32,630 | under the limit | — |
| Sullivan County | 5,750 | under the limit | — |
| Taney County | 56,744 | under the limit | — |
| Texas County | 25,715 | not sampled | — |
| Vernon County | 19,787 | under the limit | — |
| Warren County | 38,478 | under the limit | — |
| Washington County | 23,583 | not sampled | — |
| Wayne County | 10,820 | not sampled | — |
| Webster County | 42,041 | under the limit | — |
| Worth County | 1,872 | not sampled | — |
| Wright County | 19,505 | under the limit | — |