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Radon Levels in Sanpete County, Utah

EPA puts Sanpete County in Zone 1, its highest radon zone, and high results are common there: 60.0% of the 150 radon tests reported to CDC (2023) came back at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    60.0%

    23.9 pts above UT

    Sanpete
    60.0%
    Utah
    36.1%

    150 tests, 2023

  • Median result

    4.6pCi/L

    Action level reached

    Sanpete
    4.6 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2023

  • Tests reported

    150

    13th of 22 by tests

    Sanpete
    150
    Salt Lake
    9,658

    Reported to CDC before any fix, 2023

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    EPA predicts over 4 pCi/L indoors

  • Rank in Utah

    3 of 22

    Top quarter

    Sanpete
    60.0%
    Beaver
    66.7%

    By share, of 22 with 30+ tests

Read a result for Sanpete County

Starts at Sanpete County's median, 4.6 pCi/L

4.6pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 4.6 pCi/L

At or above 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. Sanpete County's median reported result, 2023.

Interpret this readingWhat a fix costs

The data

Sanpete County, At a glance

Sanpete County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Sanpete County in and predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county. That is one forecast for the whole county, not a reading of any address in it; homes above EPA's turn up in all three zones.

USGS geologic potential: High across 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Sanpete County, 2023

Share of reported tests at or above 4 pCi/L, by year, Sanpete County
Share of reported tests at or above 4 pCi/L, by year, Sanpete County
YearShare of reported tests at or above 4 pCi/L
201444.4%
201555.6%
201664.7%
201757.7%
201826.1%
201950.0%
202052.4%
202155.0%
202257.0%
202360.0%

2023: 60.0%. Across these years the share ran from 26.1% to 64.7%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 150 tests reported to CDC for Sanpete County over 2023, many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.

Measured: CDC tracking data. Figure above: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).

How to read these figures

Sanpete County, Compared

Sanpete County radon figures, compared

Calculated by Radon411

More than half: 60.0% of the 150 radon tests reported to CDC for Sanpete County in 2023 read at least 4 pCi/L. That places it 3rd of 22 Utah counties with 30 or more tests for the same period. That is 23.9 points above the 36.1% pooled from 29 Utah counties.

The median result, 4.6 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 52.5 pCi/L. The rest split 15.3% under 2 pCi/L and 24.7% from 2 to 4 (Utah: 35.4% and 28.5%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 60.0% share point the same way here.

1 of its 6 bordering counties with figures ran higher, led by Juab County at 63.3%; Carbon County reported 23.2%. Statewide for the same period, Beaver County reported the highest share (66.7%) and Washington County the lowest (9.9%).

The busiest year on file was 2022, with 237 tests reported; the quietest, 2014, had 9.

Over 3 years of annual figures the share fell 4.7 points, from 64.7% in 2016 to 60.0% in 2023; its peak was 64.7% in 2016. Nationally, every county with a figure for the same period pools to 33.4%; Sanpete County sits 26.6 points above it. CDC also counts 8 tests taken after mitigation in Sanpete County for the same period: tests in homes where a fix was already in.

Share of reported tests at or above 4 pCi/L by year, Sanpete County against Utah2016 to 2023, years with 30 or more tests: Sanpete County 64.7% to 60.0%, the state's pooled share 36.1% in 2023.
Sanpete CountyUtah, pooled
Share of reported tests at or above 4 pCi/L by year, Sanpete County against Utah: data table
YearTestsSanpete County, at or above 4 pCi/LUtah, pooled
20163464.7%39.8%
202223757.0%37.7%
202315060.0%36.1%
Sanpete County against Utah, the United States and nearby counties, 2023
AreaTestsAt or above 4 pCi/LMedianDifference from Sanpete County
Sanpete County15060.0%4.6 pCi/LThis county
Utah, pooled29 counties, pooled27,42236.1%Not pooled−23.9 points
United States, pooled642 counties, pooled128,74033.4%Not pooled−26.6 points
Beaver Countyhighest in the state4266.7%9.3 pCi/L+6.7 points
Washington Countylowest in the state6579.9%1.3 pCi/L−50.1 points
Juab County, UTborders it4963.3%5.0 pCi/L+3.3 points
Millard County, UTborders it5558.2%4.4 pCi/L−1.8 points
Sevier County, UTborders it10157.4%4.9 pCi/L−2.6 points
Utah County, UTborders it7,83340.6%3.2 pCi/L−19.4 points
Emery County, UTborders it3938.5%2.7 pCi/L−21.5 points
Carbon County, UTborders it6923.2%2.3 pCi/L−36.8 points
Where Sanpete County's reported results fell, 2023, beside Utah and the United States
ResultSanpete County testsSanpete County shareUtah shareU.S. shareAgainst Utah
Under 2 pCi/L2315.3%35.4%41.4%−20.1 points
2 to 4 pCi/L3724.7%28.5%25.2%−3.8 points
4 pCi/L and above9060.0%36.1%33.4%+23.9 points
Sanpete County ranked among the 22 Utah counties with 30 or more tests, by share at or above 4 pCi/L, 2023
CountyRankTestsAt or above 4 pCi/LMedian
Beaver County1 of 224266.7%9.3 pCi/L
Juab County2 of 224963.3%5.0 pCi/L
Sanpete County3 of 2215060.0%4.6 pCi/L
Morgan County4 of 2220759.4%5.0 pCi/L
Millard County5 of 225558.2%4.4 pCi/L
Box Elder County6 of 2244957.9%4.9 pCi/L
Sevier County7 of 2210157.4%4.9 pCi/L
Cache County8 of 2299453.8%4.4 pCi/L
Wasatch County9 of 2232451.9%4.2 pCi/L
Uintah County10 of 2210451.0%4.2 pCi/L
Tooele County11 of 2257351.0%4.1 pCi/L
Sanpete County radon tests by year, against Utah's pooled share
YearTestsAt or above 4 pCi/LMedianHighestUtah, pooledChange from the row before
202315060.0%4.6 pCi/L52.5 pCi/L36.1%+3.0 points
202223757.0%5.1 pCi/L67.7 pCi/L37.7%+2.0 points
20212055.0%5.3 pCi/L27.8 pCi/L34.2%+2.6 points
20202152.4%4.0 pCi/L11.1 pCi/L37.6%+2.4 points
20191650.0%3.9 pCi/L15.2 pCi/L37.7%+23.9 points
20182326.1%3.2 pCi/L25.1 pCi/L36.6%−31.6 points
20172657.7%4.2 pCi/L14.2 pCi/L38.2%−7.0 points
20163464.7%6.3 pCi/L34.2 pCi/L39.8%+9.1 points
20152755.6%5.1 pCi/L21.7 pCi/L42.3%+11.2 points
2014944.4%3.6 pCi/L33.7 pCi/L43.4%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Sanpete County, Geology

The ground under Sanpete County

Predicted

USGS's geologic map puts all of Sanpete County's mapped land in one class: high radon potential. 98.4% of it lies in the area the map calls Northern High Plateau, to which USGS gives a radon index of 12, in the high band (12 to 17).

USGS's geologic areas under Sanpete County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Northern High PlateauTertiary and Cretaceous sedimentary rocks.High1298.4%
Mancos Shale LowlandsMarine rocks of the Mancos shale.High131.6%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Sanpete County beside the ground around it

Sanpete County has more high-potential ground than Utah as a whole: 100% of its land against 32.8%. Of the 6 counties that border it, none has as large a share of high-potential ground; Carbon County comes nearest at 100%.

Share of land by USGS radon potential: Sanpete County, the 6 counties bordering it and Utah
AreaEPA zoneLow potentialModerate potentialHigh potential
Sanpete CountyZone 1NoneNone100%
Sevier CountyZone 1None3.3%96.7%
Emery CountyZone 2None56.3%43.7%
Carbon CountyZone 1NoneNone100%
Utah CountyZone 2None65.2%34.8%
Juab CountyZone 2None81.2%18.8%
Millard CountyZone 2None90.7%9.3%
Utah29 counties, pooled by land areaVariesNone67.2%32.8%

The map rates the ground, not the air in any home.

Local help

Sanpete County, Local resources

Radon testing and mitigation in Sanpete County

What Utah's program says
Phone
(801) 536-0091
Disclosure when a home is sold or rented
Utah requires that sellers disclose "Hazardous Conditions: Are there any hazardous conditions on the Property such as Radon gas in house or well?"

What it means

Sanpete County, Questions

Questions about radon in Sanpete County

Are radon levels high in Sanpete County?

In 2023, 60.0% of the radon tests reported to CDC for Sanpete County, Utah were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.6 pCi/L. Of 22 Utah counties with 30 or more tests for the same period, 2 reported a higher share; pooled, the state comes to 36.1%.

Which counties border Sanpete County?

Sanpete County borders 6 counties: Sevier County, Emery County, Carbon County, Utah County, Juab County and Millard County.

Products

Sanpete County, Products

Testing a home in Sanpete County

In Sanpete County, 60.0% of 150 tests reported to CDC in 2023 reached 4 pCi/L, against 36.1% pooled across Utah. In Zone 1 the year-round level in Sanpete County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.

Test kits and monitors3

See every kit and monitor

Sanpete County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Sanpete County

Explore

Sanpete County, Bordering counties

Counties bordering Sanpete County

Calculated by Radon411

Sanpete County, Cities and towns

Cities and towns in Sanpete County

Sanpete County is growing: the Census Bureau puts it at 31,453 residents on July 1, 2025, up 10.3% from 28,528 in 2020. That works out to 20 people per square mile of land. Its largest town, Ephraim, has 6,393 residents, 20.3% of the total. Together its 13 incorporated places hold 83.8% of those residents; the other 16.2% live outside any of them. Reported testing is thin here: 150 tests over 2023, or 4.8 for every 1,000 residents (2025 estimate), where Utah as a whole comes to 7.7.

From Ephraim to Fayette, CDC publishes no figure by town: each reads Sanpete County's.

The 12 largest cities and towns in Sanpete County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Ephraim6,393+13.4%20.3%
Mount Pleasant4,018+9.8%12.8%
Manti3,794+10.1%12.1%
Gunnison3,693+4.9%11.7%
Moroni1,710+10.3%5.4%
Centerfield1,482+10.3%4.7%
Fountain Green1,333+10.8%4.2%
Fairview1,328+10.2%4.2%
Spring City1,051+10.9%3.3%
Mayfield615+10.4%2.0%
Wales376+10.3%1.2%
Sterling306+10.9%1.0%
  • Fayette

13 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).

Sanpete County, Homes

Homes in Sanpete County

Sanpete County is a place of houses on their own lots: 86% of its 10,442 homes are detached single-family houses, against 67% across Utah. Half of its homes were built before 1985, close to Utah's 1991: 30% date from before 1960 and 28% from 2000 or later. Owners live in 76% of the occupied homes (Utah: 71%), so for most households a test and a fix are their own to order.

Homes in Sanpete County, Utah, 2019 to 2023
HomesSanpete CountyUtah
Housing units10,4421,193,082
Detached houses86%67%
In buildings of 5 or more4%16%
Mobile homes4%3%
Built before 196030%16%
Built since 200028%37%
Middle year built19851991
Owner-occupied76%71%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.