Salt Lake Valley radon levels by area
We compiled Utah's public radon test data for all 33 state-defined "small areas" in Salt Lake County into one sortable table and chart, with every caveat attached.
Key findings (Utah state test-kit data, 2006–2019) (Source: Utah IBIS)
- Salt Lake County: 38.6% of 25,214 short-term tests were at or above EPA's 4 pCi/L action level. The average result was 4.6 pCi/L.
- Highest area: Sandy (Northeast), averaging 7.0 pCi/L, with 56.0% of tests at or above 4.
- Lowest areas: Murray and Salt Lake City (Foothill/East Bench) at about 3.0. Even there, roughly 1 in 4 tests was at or above 4.
- Every one of the 33 areas averaged above EPA's 2 pCi/L "consider fixing" level (Source: EPA).
Average short-term radon result by area
Full table
Sorted from highest to lowest average. "95% range" is the confidence interval IBIS reports for the average: the wider it is, the less certain the average. Download as CSV.
| Area | Average, pCi/L | 95% range | Tests ≥ 4 | Tests |
|---|---|---|---|---|
| Sandy (Northeast) | 7.0 | 6.51–7.47 | 56.0% | 1,368 |
| Sandy (Southeast) | 5.8 | 5.37–6.27 | 45.0% | 1,665 |
| Riverton/Bluffdale | 5.8 | 5.33–6.29 | 48.0% | 1,862 |
| Herriman | 5.8 | 5.31–6.32 | 43.4% | 1,332 |
| West Jordan (Southeast) | 5.5 | 5.05–5.99 | 52.2% | 526 |
| South Jordan | 5.0 | 4.68–5.24 | 46.9% | 1,202 |
| Daybreak | 4.9 | 4.55–5.28 | 41.2% | 1,216 |
| West Jordan (Northeast) | 4.8 | 4.42–5.2 | 48.6% | 458 |
| Millcreek (South) | 4.7 | 4.28–5.05 | 39.7% | 910 |
| Holladay | 4.6 | 4.12–5.12 | 38.2% | 650 |
| Magna | 4.5 | 4.01–4.99 | 46.4% | 232 |
| Salt Lake City (Sugar House) | 4.5 | 4.2–4.87 | 40.9% | 1,058 |
| West Jordan (West)/Copperton | 4.5 | 4.02–4.9 | 33.4% | 692 |
| Draper | 4.5 | 4.19–4.72 | 36.3% | 1,821 |
| West Valley (Center) | 4.4 | 3.27–5.51 | 38.8% | 307 |
| Millcreek (East) | 4.3 | 3.91–4.68 | 36.8% | 850 |
| Midvale | 4.3 | 3.79–4.86 | 37.8% | 320 |
| Taylorsville (West) | 4.2 | 3.58–4.82 | 33.8% | 400 |
| Salt Lake City (Downtown) | 4.1 | 3.62–4.68 | 35.2% | 602 |
| Salt Lake City (Southeast Liberty) | 4.1 | 3.83–4.28 | 39.3% | 1,007 |
| West Valley (West) | 4.0 | 3.37–4.61 | 34.2% | 205 |
| South Salt Lake | 4.0 | 3.49–4.44 | 35.2% | 349 |
| Taylorsville (East)/Murray (West) | 4.0 | 3.58–4.36 | 35.1% | 491 |
| Salt Lake City (Glendale) | 3.7 | 2.8–4.57 | 30.4% | 123 |
| Cottonwood | 3.7 | 3.52–3.94 | 30.9% | 1,693 |
| Salt Lake City (Avenues) | 3.5 | 2.94–3.96 | 22.4% | 686 |
| West Valley (East) | 3.5 | 3.0–3.9 | 30.1% | 228 |
| Sandy (West) | 3.5 | 2.91–4.15 | 26.5% | 626 |
| Sandy (Center) | 3.3 | 3.02–3.54 | 26.6% | 601 |
| Kearns | 3.2 | 2.51–3.93 | 22.4% | 257 |
| Salt Lake City (Rose Park) | 3.1 | 2.62–3.62 | 25.8% | 242 |
| Salt Lake City (Foothill/East Bench) | 3.0 | 2.82–3.25 | 23.4% | 803 |
| Murray | 3.0 | 2.74–3.24 | 23.6% | 564 |
Area guides with housing data: Sandy · South Jordan · West Jordan · Herriman and Riverton · Draper · Millcreek · Holladay
How Salt Lake County compares with nearby counties
| County | Average short-term result, pCi/L (2006–2019) | Tests ≥ 4 | Tests |
|---|---|---|---|
| Salt Lake | 4.6 | 38.6% | 25,214 |
| Davis | 4.6 | 31.7% | 5,437 |
| Utah | 5.8 | 44.8% | 10,001 |
| Tooele | 6.2 | 50.8% | 1,212 |
| Summit | 5.5 | 39.6% | 1,347 |
| Weber | 4.9 | 35.3% | 2,631 |
| Wasatch | 10.2 | 66.4% | 1,306 |
Source: Utah IBIS-PH, same query as above (Source: Utah IBIS).
Short-term vs. long-term: why these numbers look high
Utah's separate long-term test indicator puts Salt Lake County's average at 2.9 pCi/L, Davis 2.9, Utah County 2.6, Tooele 2.4 and the state 3.2 (indicator last updated 2017) (Source: Utah IBIS). Short-term averages run higher for a few reasons:
- Placement. Short-term tests go in the lowest lived-in level, usually a basement, where radon is highest.
- Closed-house conditions. Tests are run with windows and doors shut (Source: EPA), which traps more radon than normal living does.
- Who tests. Many of these kits are bought because of a home sale or a concern, not at random. The data also includes some post-mitigation tests (Source: Utah IBIS).
So read the short-term table as where high results are common, not as the year-round average in a typical home.
Trend in Salt Lake County, by year
| Year | Average, pCi/L | Tests ≥ 4 |
|---|---|---|
| 2006 | 3.7 | 26.5% |
| 2007 | 3.9 | 37.2% |
| 2008 | 4.6 | 40.8% |
| 2009 | 4.9 | 43.5% |
| 2010 | 4.4 | 36.8% |
| 2011 | 4.9 | 38.8% |
| 2012 | 5.3 | 41.4% |
| 2013 | 4.9 | 38.2% |
| 2014 | 4.7 | 40.5% |
| 2015 | 4.8 | 41.5% |
| 2016 | 4.3 | 35.6% |
| 2017 | 4.3 | 38.0% |
| 2018 | 4.2 | 36.0% |
| 2019 | 3.9 | 33.3% |
The share of high tests has stayed in the 33–44% range every year since 2007 (Source: Utah IBIS). This is not a problem that went away.
About this data
- What it is: results from short-term test kits bought through Utah's subsidized Indoor Radon Program, in private homes, "for personal knowledge or retail transactions". Kits bought elsewhere aren't included. "Below detect" results are counted at half the detection limit (Source: Utah IBIS).
- Geography: Utah's IBIS "small areas" are state-defined groupings of ZIP codes. They don't match city limits exactly (for example, "Taylorsville (East)/Murray (West)"). Tests are assigned by the kit's shipping address.
- Years: 2006–2019. The state's dataset was last updated January 31, 2020; queries return no newer rows (Source: Utah IBIS).
- Test counts come from IBIS's "Number of radon tests" module and may not match the exact denominators behind the averages.
- Reuse: the IBIS site states its information "may be reproduced without permission". Citation: retrieved October 22, 2026 from the Utah Department of Health and Human Services, Indicator-Based Information System for Public Health, https://ibis.utah.gov/ibisph-view/.
- What we did: we ran the queries, combined the three measures into one table, sorted it and charted it. We didn't adjust any numbers.
Newer lab-based figures have been reported in local media. They use different thresholds (some use 2.7 pCi/L, not 4), and some are sponsored by testing companies, so we don't mix them into this table.
Your home is the only number that matters
An area average can't tell you your home's level. Two houses on the same street can test very differently. If you haven't tested, Utah DEQ sells low-cost kits (testing guide). If you've tested at 4 or higher, see what mitigation costs or call (801) 854-8750 to be connected with a licensed contractor.
Journalists, real-estate agents and inspectors: you're welcome to cite or link this page. Please also credit Utah IBIS-PH as the original source.
Sources
Last reviewed October 22, 2026.
- Indoor radon levels by county and ZIP, query module (short-term tests 2006–2019; dataset updated Jan. 31, 2020), Utah Dept. of Health and Human Services / Utah DEQ Indoor Radon Program. Accessed October 22, 2026.
- Home Buyer's and Seller's Guide to Radon (EPA 402/K-24/001, rev. March 2024), U.S. Environmental Protection Agency. Accessed October 22, 2026.
- Average radon levels from long-term tests, by county (indicator updated Sept. 14, 2017), Utah Dept. of Health and Human Services. Accessed October 22, 2026.