Utah County · Radon Data
Salt Lake County Radon Levels
3.6
pCi/L average
45,769
tests analyzed
1.3×
WHO threshold (2.7)
Risk classification
What 3.6 pCi/L Means for Salt Lake County Homes
High
Between 2.7–3.9 pCi/L — at or above the WHO mitigation threshold. The World Health Organization recommends mitigating homes at this level.
Salt Lake County's average of 3.6 pCi/L is 1.3× the WHO mitigation threshold of 2.7 pCi/L — well above the WHO mitigation threshold of 2.7 pCi/L. Utah's statewide average is 4.4 pCi/L, and the national average is 1.3 pCi/L.
County averages represent the arithmetic mean of all pre-mitigation tests in the area — they don't mean every home will measure exactly 3.6 pCi/L. Radon levels vary significantly based on foundation type, soil composition, construction materials, and ventilation. Two adjacent homes can have radon levels that differ by a factor of 5 or more. The only way to know your home's level is to test.
There is no safe level of radon exposure. Long-term exposure to radon is the second-leading cause of lung cancer in the US, responsible for approximately 21,000 deaths annually. The good news: mitigation systems are effective, reliable, and typically reduce radon levels by 80–99%.
City-Level Data
Radon Levels by City in Salt Lake County
22 cities with 20+ tests. Sorted highest to lowest. Click any city for detailed data and year-over-year trends.
| City | Avg pCi/L | Risk |
|---|---|---|
| Copperton | 9.6 | |
| Herriman | 4.9 | |
| Riverton | 4.9 | |
| South Jordan | 4.5 | |
| West Jordan | 4.5 | |
| Bluffdale | 4.3 | |
| Millcreek | 4.3 | |
| Garden City | 4 | |
| Holladay | 3.9 | |
| Park City | 3.9 | |
| Sandy | 3.9 | |
| Draper | 3.8 | |
| Magna | 3.3 | |
| Cottonwood Heights | 3.2 | |
| Midvale | 3.2 | |
| Taylorsville | 3.2 | |
| Murray | 3.1 | |
| Salt Lake City | 3 | |
| South Salt Lake | 2.5 | |
| West Valley City | 2.5 | |
| Myton | 2.1 | |
| Kearns | 1.8 |
Only cities with 20+ tests shown. Smaller sample sizes may not reliably represent a city's true average. All data: Alpha Energy Laboratories, 2015–August 2025.
Why Does Salt Lake County Have These Radon Levels?
Salt Lake County is Utah's most tested county by far, with 45,769 tests analyzed. Despite a moderate county average of 3.6 pCi/L, individual neighborhoods vary enormously — areas near the Wasatch foothills tend to run significantly higher than valley-floor communities. Testing your specific home remains essential regardless of neighborhood averages.
Regardless of county-level geology, the only authoritative measurement for any home is a test conducted inside that specific building. Foundation type, crawl space vs. slab construction, and ventilation all dramatically affect indoor levels — which is why testing every home individually is the only reliable approach.
Salt Lake County Radon — Frequently Asked Questions
What is the average radon level in Salt Lake County, Utah?
Salt Lake County has an average indoor radon level of 3.6 pCi/L based on 45,769 pre-mitigation tests analyzed by Alpha Energy Laboratories from 2015 through August 2025. This is 1.3× the WHO's recommended mitigation threshold of 2.7 pCi/L and 0.8× Utah's statewide average of 4.4 pCi/L.
Is radon a serious concern in Salt Lake County?
Yes. Salt Lake County's average of 3.6 pCi/L is classified as high. Between 2.7–3.9 pCi/L — at or above the WHO mitigation threshold. The World Health Organization recommends mitigating homes at this level. Radon is the second-leading cause of lung cancer in the United States after smoking, responsible for approximately 21,000 deaths annually.
Which cities in Salt Lake County have the highest radon levels?
Based on test data, the highest-averaging cities in Salt Lake County are: Copperton (9.6 pCi/L, 33 tests), Herriman (4.9 pCi/L, 2,005 tests), Riverton (4.9 pCi/L, 2,115 tests). Remember that city averages can mask significant variation between individual homes.
How do I get a radon test in Salt Lake County, Utah?
Utah Radon provides free certified radon test kits to Utah homeowners, including those in Salt Lake County. The kit is mailed to your home, you place it according to instructions, mail it back to Alpha Energy Laboratories, and receive your results within 2–3 weeks. There is no cost for the kit, shipping, or lab analysis. Request yours at utahradon.org/free-test-kit.
Protect your Salt Lake County home
With a county average of 3.6 pCi/L — 1.3× the WHO mitigation threshold — Salt Lake County homes should be tested. Your free kit is waiting.
Request your free test kit