Your county health department
Wyoming 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.
Wyoming's private well pageArsenic in Wyoming well water, by county
Arsenic is widespread, over the limit in 15% or more of tested wells, in 2 of the 16 Wyoming 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 Wyoming compares with the rest of the country
Across Wyoming, about 1 in 18 tested wells had arsenic over the EPA limit of 10 µg/L (23 of 425). Across all tested wells in the US it's about 1 in 9. That's less often than in the country as a whole. Counties still differ, so check yours 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 |
|---|---|---|---|
| Park County | 14 | Widespread | |
| Converse County | 23 | Widespread | |
| Sweetwater County | 38 | Worth checking | |
| Carbon County | 60 | Worth checking | |
| Laramie County | 34 | Worth checking | |
| Goshen County | 25 | Rare | |
| Campbell County | 26 | Rare | |
| Sheridan County | 34 | Rare | |
| Platte County | 28 | Rare | |
| Albany County | 25 | Rare | |
| Niobrara County | 24 | Rare | |
| Sublette County | 23 | Rare | |
| Crook County | 17 | Rare | |
| Fremont County | 11 | Rare | |
| Teton County | 10 | Rare | |
| Washakie County | 10 | Rare |
4 more Wyoming counties have 1 to 9 tested wells for arsenic, too few to rate.
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Where to get your well tested for arsenic in Wyoming
A lab Wyoming certifies
Ask for arsenic by name. Results from a certified lab count for a home sale or a loan.
Labs certified by WyomingA 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 Wyoming
- Well water testing in Wyoming: 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 Wyoming wells, by county
- Uranium in Wyoming wells, by county
- Manganese in Wyoming wells, by county
- Lead in Wyoming wells, by county
- Radon in Wyoming wells, by county
Questions people ask about arsenic in Wyoming
Is there arsenic in Wyoming well water?
Arsenic is widespread, over the limit in 15% or more of tested wells, in 2 of the 16 Wyoming counties with 10 or more tested wells. Across Wyoming, about 1 in 18 tested wells had arsenic over the EPA limit of 10 µg/L (23 of 425). Across all tested wells in the US it's about 1 in 9. That's less often than in the country as a whole. Counties still differ, so check yours below.
Where can I get my well tested for arsenic in Wyoming?
Use a lab certified by Wyoming 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 Wyoming'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 Environmental Quality (DEQ), Know Your Well program.