Your county health department
Oklahoma 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.
Oklahoma's private well pageArsenic in Oklahoma well water, by county
Arsenic is widespread, over the limit in 15% or more of tested wells, in 3 of the 7 Oklahoma 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 Oklahoma compares with the rest of the country
Across Oklahoma, about 2 in 10 tested wells had arsenic over the EPA limit of 10 µg/L (57 of 278). Across all tested wells in the US it's about 1 in 9. So arsenic turns up somewhat more often in Oklahoma than in the country as a whole. Check your county 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 |
|---|---|---|---|
| Cleveland County | 65 | Widespread | |
| Oklahoma County | 42 | Widespread | |
| Osage County | 23 | Widespread | |
| Pottawatomie County | 55 | Rare | |
| Johnston County | 21 | Rare | |
| Murray County | 12 | Rare | |
| Lincoln County | 10 | Rare |
20 more Oklahoma counties have 1 to 9 tested wells for arsenic, too few to rate.
Download this table (CSV) · Free to reuse under CC BY 4.0
Where to get your well tested for arsenic in Oklahoma
A lab Oklahoma certifies
Ask for arsenic by name. Results from a certified lab count for a home sale or a loan.
Labs certified by OklahomaA 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 Oklahoma
- Well water testing in Oklahoma: 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 Oklahoma wells, by county
- Uranium in Oklahoma wells, by county
- Manganese in Oklahoma wells, by county
- Lead in Oklahoma wells, by county
Questions people ask about arsenic in Oklahoma
Is there arsenic in Oklahoma well water?
Arsenic is widespread, over the limit in 15% or more of tested wells, in 3 of the 7 Oklahoma counties with 10 or more tested wells. Across Oklahoma, about 2 in 10 tested wells had arsenic over the EPA limit of 10 µg/L (57 of 278). Across all tested wells in the US it's about 1 in 9. So arsenic turns up somewhat more often in Oklahoma than in the country as a whole. Check your county below.
Where can I get my well tested for arsenic in Oklahoma?
Use a lab certified by Oklahoma 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 Oklahoma'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.