Water quality by county
in Maryland
EPA sampled public water systems across Maryland for PFAS under its UCMR 5 programme. Of the 24 counties, 8 have a reading above a federal limit and 1 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 |
|---|---|---|---|
| Frederick County | 299,317 | 12× | PFOS · 48 ng/L |
| Cecil County | 106,305 | 5.8× | PFOA · 23.3 ng/L |
| Wicomico County | 106,329 | 5.0× | PFOS · 20 ng/L |
| Carroll County | 177,108 | 3.2× | PFOA · 12.7 ng/L |
| Howard County | 339,668 | 2.5× | PFOA · 10 ng/L |
| Harford County | 265,514 | 2.3× | PFOA · 9.3 ng/L |
| Washington County | 157,228 | 1.7× | PFOA · 6.7 ng/L |
| Montgomery County | 1,082,273 | 1.6× | PFOS · 6.5 ng/L |
| Worcester County | 54,337 | under the limit | PFHxS · 4.9 ng/L |
| Allegany County | 67,097 | under the limit | — |
| Anne Arundel County | 602,350 | under the limit | — |
| Baltimore County | 568,271 | under the limit | — |
| Baltimore City | 568,271 | under the limit | — |
| Calvert County | 94,913 | under the limit | — |
| Caroline County | 34,248 | under the limit | — |
| Charles County | 174,478 | under the limit | — |
| Dorchester County | 33,138 | under the limit | — |
| Garrett County | 28,393 | not sampled | — |
| Kent County | 19,557 | under the limit | — |
| Prince George's County | 966,629 | under the limit | — |
| Queen Anne's County | 53,688 | under the limit | — |
| Somerset County | 25,241 | under the limit | — |
| St. Mary's County | 116,469 | under the limit | — |
| Talbot County | 38,244 | under the limit | — |