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Radon Levels in Davis County, Utah

EPA puts Davis County in Zone 2, its middle radon zone, and 28.4% of its 3,594 reported radon tests (2023) were 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

    28.4%

    7.7 pts below UT

    Davis
    28.4%
    Utah
    36.1%

    3,594 tests, 2023

  • Median result

    2.4pCi/L

    Below action level

    Davis
    2.4 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2023

  • Tests reported

    3,594

    3rd of 22 by tests

    Davis
    3,594
    Salt Lake
    9,658

    Reported to CDC before any fix, 2023

  • EPA radon zone

    Zone 2

    Moderate potential

    1. 1
    2. Zone 2
    3. 3

    1 highest, 3 lowest

    EPA predicts 2 to 4 pCi/L indoors

  • Rank in Utah

    18 of 22

    Lowest quarter

    Davis
    28.4%
    Beaver
    66.7%

    By share, of 22 with 30+ tests

Read a result for Davis County

Starts at Davis County's median, 2.4 pCi/L

2.4pCi/L

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

EPA’s reading of 2.4 pCi/L

Between 2 and 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 between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Davis County's median reported result, 2023.

Interpret this readingWhat a fix costs

The data

Davis County, At a glance

Davis County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Davis County is a county: EPA's forecast for it as a whole is an average indoor of 2 to 4 pCi/L (75 to 150 Bq/m³). It describes no single address, and homes above EPA's are found in every zone, this one included.

USGS geologic potential: Moderate across 86% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Davis County, 2023

Share of reported tests at or above 4 pCi/L, by year, Davis County
Share of reported tests at or above 4 pCi/L, by year, Davis County
YearShare of reported tests at or above 4 pCi/L
201431.8%
201534.2%
201634.0%
201728.5%
201829.2%
201930.1%
202034.6%
202129.8%
202232.2%
202328.4%

2023: 28.4%. Across these years the share ran from 28.4% to 34.6%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 3,594 tests reported to CDC for Davis 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

Davis County, Compared

Davis County radon figures, compared

Calculated by Radon411

Davis County's 3,594 reported tests in 2023 had a middle value of 2.4 pCi/L and a maximum of 348.8 pCi/L, and 28.4% reached 4 pCi/L. Utah as a whole (29 Utah counties, pooled) comes to 36.1%: 7.7 points higher than here.

Among its state's counties it ranks 18th of 22 Utah counties with 30 or more tests for the same period. Statewide for the same period, Beaver County reported the highest share (66.7%) and Washington County the lowest (9.9%).

Below the action level, 1,482 tests (41.2%) came in under 2 pCi/L, against 35.4% statewide, and 1,090 tests (30.3%) fell between 2 and 4, against 28.5% statewide. The busiest year on file was 2022, with 4,641 tests reported; the quietest, 2019, had 306.

EPA's 1993 zone map puts Davis County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 86% of the county's land moderate radon potential.

Next door, the shares run from 28.6% in Weber County to 59.4% in Morgan County. Over 10 years of annual figures the share fell 3.4 points, from 31.8% in 2014 to 28.4% in 2023; its peak was 34.6% in 2020.

CDC also counts 401 tests taken after mitigation in Davis 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, Davis County against Utah2014 to 2023, years with 30 or more tests: Davis County 31.8% to 28.4%, the state's pooled share 36.1% in 2023.
Davis CountyUtah, pooled
Share of reported tests at or above 4 pCi/L by year, Davis County against Utah: data table
YearTestsDavis County, at or above 4 pCi/LUtah, pooled
201438131.8%43.4%
201554434.2%42.3%
201679834.0%39.8%
201759928.5%38.2%
201852029.2%36.6%
201930630.1%37.7%
202049134.6%37.6%
202149329.8%34.2%
20224,64132.2%37.7%
20233,59428.4%36.1%
Davis County against Utah, the United States and nearby counties, 2023
AreaTestsAt or above 4 pCi/LMedianDifference from Davis County
Davis County3,59428.4%2.4 pCi/LThis county
Utah, pooled29 counties, pooled27,42236.1%Not pooled+7.7 points
United States, pooled642 counties, pooled128,74033.4%Not pooled+5.0 points
Beaver Countyhighest in the state4266.7%9.3 pCi/L+38.3 points
Washington Countylowest in the state6579.9%1.3 pCi/L−18.5 points
Morgan County, UTborders it20759.4%5.0 pCi/L+31.0 points
Box Elder County, UTborders it44957.9%4.9 pCi/L+29.5 points
Tooele County, UTborders it57351.0%4.1 pCi/L+22.6 points
Salt Lake County, UTborders it9,65833.1%2.6 pCi/L+4.7 points
Weber County, UTborders it1,66928.6%2.1 pCi/L+0.2 points
Where Davis County's reported results fell, 2023, beside Utah and the United States
ResultDavis County testsDavis County shareUtah shareU.S. shareAgainst Utah
Under 2 pCi/L1,48241.2%35.4%41.4%+5.8 points
2 to 4 pCi/L1,09030.3%28.5%25.2%+1.8 points
4 pCi/L and above1,02228.4%36.1%33.4%−7.7 points
Davis 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
Utah County12 of 227,83340.6%3.2 pCi/L
Duchesne County13 of 228139.5%3.2 pCi/L
Emery County14 of 223938.5%2.7 pCi/L
Salt Lake County15 of 229,65833.1%2.6 pCi/L
Summit County16 of 2241732.6%2.4 pCi/L
Weber County17 of 221,66928.6%2.1 pCi/L
Davis County18 of 223,59428.4%2.4 pCi/L
Grand County19 of 224623.9%1.9 pCi/L
Carbon County20 of 226923.2%2.3 pCi/L
Iron County21 of 2221321.1%2.1 pCi/L
Washington County22 of 226579.9%1.3 pCi/L
Davis County radon tests by year, against Utah's pooled share
YearTestsAt or above 4 pCi/LMedianHighestUtah, pooledChange from the row before
20233,59428.4%2.4 pCi/L348.8 pCi/L36.1%−3.8 points
20224,64132.2%2.5 pCi/L1070.0 pCi/L37.7%+2.4 points
202149329.8%2.2 pCi/L198.6 pCi/L34.2%−4.8 points
202049134.6%2.5 pCi/L40.7 pCi/L37.6%+4.5 points
201930630.1%2.3 pCi/L64.0 pCi/L37.7%+0.9 points
201852029.2%2.6 pCi/L208.3 pCi/L36.6%+0.7 points
201759928.5%2.2 pCi/L68.4 pCi/L38.2%−5.5 points
201679834.0%2.8 pCi/L100.6 pCi/L39.8%−0.2 points
201554434.2%2.8 pCi/L215.0 pCi/L42.3%+2.4 points
201438131.8%2.3 pCi/L46.2 pCi/L43.4%First on file

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

Davis County, Geology

The ground under Davis County

Predicted

Most of the ground under Davis County is one class on USGS's geologic map: 85.9% of its land is moderate radon potential, with 14.1% high. The map puts 85.9% of Davis County in the area it calls Basin and Range and 14.1% in Wasatch Range. USGS gives the first a radon index of 11, in the moderate band (9 to 11), and the second 14, in the high band (12 to 17).

USGS's geologic areas under Davis County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Basin and RangeQuaternary sedimentary and igneous rocks.Moderate1185.9%
Wasatch RangePrecambrian granite and gneiss and Tertiary igneous rocks that have relatively low uranium concentrations.High1414.1%

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

Davis County beside the ground around it

Utah as a whole has more high-potential ground than Davis County: 32.8% of its land, against 14.1% here. Of the 5 counties that border it, 3 have more high-potential ground, Morgan County the most at 99.7%.

Share of land by USGS radon potential: Davis County, the 5 counties bordering it and Utah
AreaEPA zoneLow potentialModerate potentialHigh potential
Davis CountyZone 2None85.9%14.1%
Weber CountyZone 2None56.7%43.3%
Salt Lake CountyZone 2None68.3%31.7%
Morgan CountyZone 2None0.3%99.7%
Box Elder CountyZone 2None97.4%2.6%
Tooele CountyZone 2None100%None
Utah29 counties, pooled by land areaVariesNone67.2%32.8%

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

Local help

Davis County, Local resources

Radon testing and mitigation in Davis 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

Davis County, Questions

Questions about radon in Davis County

Are radon levels high in Davis County?

In 2023, 28.4% of the radon tests reported to CDC for Davis County, Utah were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.4 pCi/L. Of 22 Utah counties with 30 or more tests for the same period, 17 reported a higher share; pooled, the state comes to 36.1%.

Which counties border Davis County?

Davis County borders 5 counties: Weber County, Salt Lake County, Morgan County, Box Elder County and Tooele County.

Products

Davis County, Products

Testing a home in Davis County

In Davis County, 28.4% of 3,594 tests reported to CDC in 2023 reached 4 pCi/L, against 36.1% pooled across Utah. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Davis County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Davis County homes, compared

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Davis County, Bordering counties

Counties bordering Davis County

Calculated by Radon411

Davis County, Cities and towns

Cities and towns in Davis County

The Census Bureau estimates 381,227 residents in Davis County for July 1, 2025, 17,461 more than in 2020 (+4.8%). Packed into its land, that is 1,275 people per square mile. Its largest town, Layton, has 85,308 residents, 22.4% of the total. Together its 15 incorporated places hold 99.4% of those residents; the other 0.6% live outside any of them. CDC's 3,594 reported tests for 2023 work out to 9.4 per 1,000 residents (2025 estimate), close to Utah's 7.7.

From Layton to Sunset, CDC publishes no figure by town: each reads Davis County's.

The 12 largest cities and towns in Davis County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Layton85,308+3.9%22.4%
Bountiful44,988−1.8%11.8%
Syracuse39,909+23.2%10.5%
Clearfield35,144+10.1%9.2%
Kaysville33,307+0.8%8.7%
Farmington26,266+6.9%6.9%
Clinton23,797+1.4%6.2%
North Salt Lake23,588+2.2%6.2%
Centerville16,480−2.1%4.3%
West Point13,058+17.6%3.4%
Woods Cross11,429−0.1%3.0%
South Weber8,218+3.0%2.2%
  • Fruit Heights
  • West Bountiful
  • Sunset

15 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).

Davis County, Homes

Homes in Davis County

Davis County is a place of houses on their own lots: 75% of its 118,581 homes are detached single-family houses, against 67% across Utah. Half of its homes were built before 1993, close to Utah's 1991: 10% date from before 1960 and 39% from 2000 or later. Owners live in 77% of the occupied homes (Utah: 71%), so for most households a test and a fix are their own to order.

Homes in Davis County, Utah, 2019 to 2023
HomesDavis CountyUtah
Housing units118,5811,193,082
Detached houses75%67%
In buildings of 5 or more11%16%
Mobile homes2%3%
Built before 196010%16%
Built since 200039%37%
Middle year built19931991
Owner-occupied77%71%

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