Your county health department
Arizona doesn't run a statewide free testing program that we know of. Some county health departments test wells or sell kits, so call yours first.
Arizona's private well pageArsenic in Arizona well water, by county
Arsenic is widespread, over the limit in 15% or more of tested wells, in 8 of the 15 Arizona counties with 10 or more tested wells. A county's share tells you how likely a problem is nearby. Only a test of your own well tells you what's in it.
How Arizona compares with the rest of the country
Across Arizona, about 1 in 4 tested wells had arsenic over the EPA limit of 10 µg/L (542 of 2,320). Across all tested wells in the US it's about 1 in 9. So arsenic turns up in Arizona wells about twice as often as in the country as a whole, and a test is worth adding even if your county isn't on the list below.
Why it matters: Drinking it for years raises the risk of skin, bladder and lung cancer.
Arsenic dissolves out of certain rocks and old sediments, so it can be high even where nobody has polluted anything.
Arsenic in tested wells, county by county
Share of each county's tested wells with at least one result over the EPA limit of 10 µg/L. Counties need 10 or more tested wells to be listed. Widespread means 15% or more, worth checking 5 to 15%, rare under 5%.
| County | Wells tested | Wells over the limit | Level |
|---|---|---|---|
| Yuma County | 103 | Widespread | |
| Maricopa County | 416 | Widespread | |
| Graham County | 136 | Widespread | |
| La Paz County | 182 | Widespread | |
| Pinal County | 161 | Widespread | |
| Yavapai County | 238 | Widespread | |
| Greenlee County | 56 | Widespread | |
| Mohave County | 327 | Widespread | |
| Gila County | 138 | Worth checking | |
| Santa Cruz County | 74 | Worth checking | |
| Cochise County | 158 | Worth checking | |
| Navajo County | 81 | Worth checking | |
| Pima County | 134 | Worth checking | |
| Apache County | 48 | Worth checking | |
| Coconino County | 68 | Worth checking |
Download this table (CSV) · Free to reuse under CC BY 4.0
Where to get your well tested for arsenic in Arizona
A lab Arizona certifies
Ask for arsenic by name. Results from a certified lab count for a home sale or a loan.
Labs certified by ArizonaA mail-in kit
Fill the bottles at your kitchen tap and mail them back. We mark the kits that include arsenic.
Compare kitsKeep reading about wells in Arizona
- Well water testing in Arizona: how to get tested and what turns up statewide
- Arsenic in well water: where it comes from, what it does and how to remove it
- Nitrate in Arizona wells, by county
- Uranium in Arizona wells, by county
- Manganese in Arizona wells, by county
- Lead in Arizona wells, by county
- Radon in Arizona wells, by county
Questions people ask about arsenic in Arizona
Is there arsenic in Arizona well water?
Arsenic is widespread, over the limit in 15% or more of tested wells, in 8 of the 15 Arizona counties with 10 or more tested wells. Across Arizona, about 1 in 4 tested wells had arsenic over the EPA limit of 10 µg/L (542 of 2,320). Across all tested wells in the US it's about 1 in 9. So arsenic turns up in Arizona wells about twice as often as in the country as a whole, and a test is worth adding even if your county isn't on the list below.
Where can I get my well tested for arsenic in Arizona?
Use a lab certified by Arizona for drinking water, or a mail-in kit that includes arsenic from a certified lab. Some county health departments test wells too, so call yours first.
See Arizona's list of certified labs, or compare mail-in kits.
Where these numbers come from
- Lab tests: Water Quality Portal (USGS and EPA), well samples since 2000. A well counts as over if any of its tests was over the EPA limit of 10 µg/L. Wells tested for studies and monitoring, not a random sample of homes.
- Likely overstated: our own check of who tested the wells, when and where. How we check.
- State programs and links: Department of Health Services.