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 pageNitrate in Wyoming well water, by county
Nitrate is widespread, over the limit in 15% or more of tested wells, in 3 of the 21 Wyoming counties with 10 or more tested wells. 1 more look high, but those results likely overstate it. 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 15 tested wells had nitrate over the EPA limit of 10 mg/L (46 of 680). Across all tested wells in the US it's about 1 in 12. Wyoming is about average, so the county you live in tells you more than the state does.
Why it matters: It's dangerous for babies under 6 months, because it keeps their blood from carrying enough oxygen.
Nitrate soaks down into groundwater from fertilizer, manure and septic systems.
Nitrate in tested wells, county by county
Share of each county's tested wells with at least one result over the EPA limit of 10 mg/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 |
|---|---|---|---|
| Johnson County | 35 | Widespread | |
| Natrona County | 14 | Widespread | |
| Goshen County | 40 | Widespread | |
| Hot Springs County | 11 | Widespread | |
| Niobrara County | 25 | Worth checking | |
| Sweetwater County | 40 | Worth checking | |
| Washakie County | 14 | Worth checking | |
| Converse County | 29 | Worth checking | |
| Uinta County | 15 | Worth checking | |
| Platte County | 38 | Worth checking | |
| Carbon County | 63 | Rare | |
| Park County | 22 | Rare | |
| Campbell County | 47 | Rare | |
| Crook County | 30 | Rare | |
| Albany County | 34 | Rare | |
| Laramie County | 41 | Rare | |
| Sheridan County | 51 | Rare | |
| Teton County | 49 | Rare | |
| Sublette County | 33 | Rare | |
| Big Horn County | 23 | Rare | |
| Fremont County | 18 | Rare |
* Likely overstated. These shares come from a narrow set of wells, so they probably run high for the county as a whole:
- Hot Springs County: All of these tests come from the US Geological Survey, mostly before 2013 in one small part of the county, so this likely overstates it.
2 more Wyoming counties have 1 to 9 tested wells for nitrate, too few to rate.
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Where to get your well tested for nitrate in Wyoming
A lab Wyoming certifies
Ask for nitrate 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 nitrate.
Compare kitsKeep reading about wells in Wyoming
- Well water testing in Wyoming: how to get tested and what turns up statewide
- Nitrate in well water: where it comes from, what it does and how to remove it
- Arsenic 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 nitrate in Wyoming
Is there nitrate in Wyoming well water?
Nitrate is widespread, over the limit in 15% or more of tested wells, in 3 of the 21 Wyoming counties with 10 or more tested wells. 1 more look high, but those results likely overstate it. Across Wyoming, about 1 in 15 tested wells had nitrate over the EPA limit of 10 mg/L (46 of 680). Across all tested wells in the US it's about 1 in 12. Wyoming is about average, so the county you live in tells you more than the state does.
Where can I get my well tested for nitrate in Wyoming?
Use a lab certified by Wyoming for drinking water, or a mail-in kit that includes nitrate 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 mg/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.