Water quality by county
in Arizona
EPA sampled public water systems across Arizona for PFAS under its UCMR 5 programme. Of the 15 counties, 9 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 |
|---|---|---|---|
| Maricopa County | 4,673,096 | 14× | PFOS · 55.8 ng/L |
| Gila County | 54,073 | 11× | PFOS · 42.2 ng/L |
| Santa Cruz County | 50,508 | 10× | PFOS · 40.9 ng/L |
| Pima County | 1,080,149 | 5.8× | PFOS · 23 ng/L |
| Yavapai County | 252,013 | 5.3× | PFOA · 21 ng/L |
| Pinal County | 513,862 | 4.8× | PFOA · 19 ng/L |
| Coconino County | 145,161 | 2.5× | PFOA · 10 ng/L |
| Cochise County | 125,773 | 2.4× | PFOA · 9.7 ng/L |
| Mohave County | 226,479 | 1.8× | PFOS · 7.3 ng/L |
| Yuma County | 220,310 | under the limit | PFHxS · 3.1 ng/L |
| Apache County | 64,800 | under the limit | — |
| Graham County | 40,242 | under the limit | — |
| Greenlee County | 9,410 | under the limit | — |
| La Paz County | 16,992 | not sampled | — |
| Navajo County | 109,516 | under the limit | — |