Radon levels in Wyoming: Moderate
The model predicts a population-weighted basement average of 3.0 pCi/L (model estimate) across Wyoming's 23 counties - about 1.7× the US average of 1.8 pCi/L. Above-ground floors average 2.1 pCi/L.
Predicted (model estimate). The pCi/L figures on this page are long-term area averages from a peer-reviewed national model built on millions of real radon tests (2001-2021). They describe the typical home in this area - not your home, which can be several times higher or lower. The EPA radon zone is a separate, 1993 county-level classification. How the numbers work.
21 / 23
EPA Zone 1 counties (91%)
2 / 0
Zone 2 / Zone 3 counties
1
counties predicted ≥ 4 pCi/L
2.9%
of ZIP codes predicted ≥ 4 pCi/L
Test Wyoming - the EPA says "consider fixing" in this range
The predicted basement average here is 3.0 pCi/L, in the 2-4 pCi/L band where the EPA recommends considering mitigation. Plenty of individual homes in a moderate area test above 4. Start with a short-term test; if it comes back at 2 or higher, follow up with a long-term test or a continuous monitor.
Monitor link goes to the Airthings store - use code RADONGRADE-10OFF at checkout for 10% off any Airthings monitor.
Already tested at 4 pCi/L or higher? Find a certified mitigation professional (EPA). A mitigation system typically runs $800-$2,500 installed.
Affiliate links: we may earn a commission from Airthings or Amazon at no extra cost to you.
What the data says about radon in Wyoming
21 of Wyoming's 23 counties are EPA Zone 1 (91%), 2 are Zone 2 and 0 are Zone 3 on the EPA's county-level map. Zone 1 - the highest-potential class, predicted screening average above 4 pCi/L - is the most common designation in Wyoming. The zones were drawn once, from geology and the tests available in 1993, and the EPA itself notes that homes with elevated radon exist in all three zones.
Weighted by where people live, Wyoming's predicted basement average is 3.0 pCi/L - 1.7× the US population-weighted average of 1.8 - which puts the state in the moderate range. Of the 23 counties with predictions, 1 are predicted at or above 4 pCi/L, 22 in the 2-4 band and 0 below 2. The highest predicted county is Lincoln County at 4.1 pCi/L; the lowest is Albany County at 2.4 - a 1.7 pCi/L spread that means a statewide average tells you little about any one county.
Nationally 4.2% of ZIPs are predicted at 4+ pCi/L and 48.7% at 2+; in Wyoming it is 2.9% and 100% - below the US share at the action level but above it at 2 pCi/L. With more than half of ZIPs above 2, a test is worth doing before any purchase or renovation here.
Wyoming counties by predicted radon
Sorted highest to lowest predicted basement average (model estimate). 23 counties.
| County | Predicted basement | Upstairs | Grade | EPA zone | ZIPs |
|---|---|---|---|---|---|
| Lincoln County | 4.1 pCi/L | 2.6 | High | EPA Zone 1 | 11 |
| Sheridan County | 3.9 pCi/L | 2.6 | Moderate | EPA Zone 1 | 8 |
| Weston County | 3.9 pCi/L | 2.6 | Moderate | EPA Zone 2 | 3 |
| Converse County | 3.6 pCi/L | 2.4 | Moderate | EPA Zone 1 | 4 |
| Fremont County | 3.3 pCi/L | 2.5 | Moderate | EPA Zone 1 | 10 |
| Crook County | 3.3 pCi/L | 2.1 | Moderate | EPA Zone 1 | 6 |
| Big Horn County | 3.2 pCi/L | 2.2 | Moderate | EPA Zone 1 | 9 |
| Teton County | 3.2 pCi/L | 2.4 | Moderate | EPA Zone 1 | 6 |
| Park County | 3.2 pCi/L | 2.3 | Moderate | EPA Zone 1 | 4 |
| Natrona County | 3.1 pCi/L | 2.2 | Moderate | EPA Zone 1 | 6 |
| Hot Springs County | 3.1 pCi/L | 2.4 | Moderate | EPA Zone 1 | 2 |
| Niobrara County | 3.0 pCi/L | 1.8 | Moderate | EPA Zone 1 | 4 |
| Carbon County | 3.0 pCi/L | 2.2 | Moderate | EPA Zone 1 | 9 |
| Campbell County | 3.0 pCi/L | 2.0 | Moderate | EPA Zone 1 | 7 |
| Sweetwater County | 2.8 pCi/L | 2.1 | Moderate | EPA Zone 1 | 6 |
| Johnson County | 2.8 pCi/L | 1.8 | Moderate | EPA Zone 1 | 2 |
| Sublette County | 2.8 pCi/L | 2.2 | Moderate | EPA Zone 1 | 6 |
| Uinta County | 2.7 pCi/L | 1.8 | Moderate | EPA Zone 1 | 2 |
| Washakie County | 2.7 pCi/L | 2.1 | Moderate | EPA Zone 1 | 2 |
| Platte County | 2.6 pCi/L | 1.8 | Moderate | EPA Zone 2 | 5 |
| Goshen County | 2.6 pCi/L | 1.9 | Moderate | EPA Zone 1 | 8 |
| Laramie County | 2.5 pCi/L | 1.8 | Moderate | EPA Zone 1 | 9 |
| Albany County | 2.4 pCi/L | 2.0 | Moderate | EPA Zone 1 | 8 |
Radon levels in Wyoming cities
The 2 most-populous Wyoming places among the 1,000 largest US cities (Census incorporated places and CDPs), by population. City figures are ZIP-land-weighted means of the model's ZIP predictions (model estimate).
Highest-radon ZIP codes in Wyoming
The 10 Wyoming ZIP codes with the highest predicted basement average (model estimate), out of 137 modeled. A ZIP average is still an area figure - neighboring homes routinely test several pCi/L apart.
| ZIP | County | Predicted basement | Upstairs | Grade |
|---|---|---|---|---|
| 83110 | Lincoln County | 6.0 pCi/L | 3.1 | High |
| 83127 | Lincoln County | 4.2 pCi/L | 2.8 | High |
| 82801 | Sheridan County | 4.1 pCi/L | 2.7 | High |
| 82701 | Weston County | 4.1 pCi/L | 2.6 | High |
| 83112 | Lincoln County | 3.9 pCi/L | 2.6 | Moderate |
| 82633 | Converse County | 3.8 pCi/L | 2.6 | Moderate |
| 83122 | Lincoln County | 3.8 pCi/L | 2.6 | Moderate |
| 83128 | Lincoln County | 3.7 pCi/L | 2.8 | Moderate |
| 82609 | Natrona County | 3.6 pCi/L | 2.1 | Moderate |
| 82730 | Weston County | 3.6 pCi/L | 2.4 | Moderate |
Wyoming radon questions
- Is radon high in Wyoming?
- Wyoming's population-weighted predicted basement average is 3.0 pCi/L, about 1.7× the US average of 1.8. 1 of its 23 modeled counties are predicted at or above the EPA action level of 4 pCi/L, 22 are in the 2-4 "consider fixing" range and 0 are below 2. 2.9% of Wyoming ZIP codes are predicted at 4 or higher.
- Which Wyoming county has the highest radon?
- Lincoln County has the highest predicted basement average in Wyoming at 4.1 pCi/L (EPA Zone 1). The lowest is Albany County at 2.4 pCi/L. These are area figures; individual homes in any county can test far higher.
- How many EPA Zone 1 counties are in Wyoming?
- 21 of Wyoming's 23 counties (91%) are EPA Zone 1 (highest potential), 2 are Zone 2 and 0 are Zone 3. The EPA zone map dates from 1993; the predicted values on this page come from a 2001-2021 model built on millions of actual tests, so the two can disagree for a given county.
- Should I test for radon in Wyoming?
- Yes - with some urgency. Wyoming's predicted average is in the moderate range, and 100% of its ZIP codes are predicted at 2 pCi/L or higher. A short-term charcoal kit or a continuous digital monitor will tell you your actual level within days.
Wyoming radon program
State programs keep lists of certified testers and mitigators and sometimes run kit programs. We link only pages we could verify, and Wyoming's program page did not respond when we checked, so start from the EPA state radon contacts page. Then read how to test and what mitigation costs.