Skip to content
RADON411

Locations and reports

Radon Levels in Leon County, Florida

EPA puts Leon County in Zone 2, its middle radon zone, and 19.1% of its 1,196 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

    19.1%

    0.6 pts above FL

    Leon
    19.1%
    Florida
    18.5%

    1,196 tests, 2023

  • Median result

    1.8pCi/L

    Below action level

    Leon
    1.8 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2023

  • Tests reported

    1,196

    6th of 30 by tests

    Leon
    1,196
    Broward
    2,165

    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 Florida

    8 of 30

    Top quarter

    Leon
    19.1%
    Marion
    44.5%

    By share, of 30 with 30+ tests

Read a result for Leon County

Starts at Leon County's median, 1.8 pCi/L

1.8pCi/L

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

EPA’s reading of 1.8 pCi/L

Below 2 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 below 2 pCi/L, the level at which EPA says a fix should be considered. Leon County's median reported result, 2023.

Interpret this reading

The data

Leon County, At a glance

Leon County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Leon 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: Low across 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Leon County, 2023

Share of reported tests at or above 4 pCi/L, by year, Leon County
Share of reported tests at or above 4 pCi/L, by year, Leon County
YearShare of reported tests at or above 4 pCi/L
201426.9%
201522.2%
201617.7%
201723.5%
201822.1%
201916.8%
202023.5%
202119.4%
202216.4%
202319.1%

2023: 19.1%. Across these years the share ran from 16.4% to 26.9%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 1,196 tests reported to CDC for Leon 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

Leon County, Compared

Leon County radon figures, compared

Calculated by Radon411

Leon County's 1,196 reported tests in 2023 had a middle value of 1.8 pCi/L and a maximum of 16.7 pCi/L, and 19.1% reached 4 pCi/L. Florida as a whole (49 Florida counties, pooled) comes to 18.5%: 0.6 points lower than here.

Among its state's counties it ranks 8th of 30 Florida counties with 30 or more tests for the same period. Statewide for the same period, Marion County reported the highest share (44.5%) and Clay County the lowest (0.0%).

Below the action level, 633 tests (52.9%) came in under 2 pCi/L, against 57.3% statewide, and 334 tests (27.9%) fell between 2 and 4, against 24.2% statewide. The busiest year on file was 2022, with 4,296 tests reported; the quietest, 2014, had 826.

EPA's 1993 zone map puts Leon County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 100% of the county's land low radon potential.

Next door, the shares run from 3.2% in Wakulla County to 14.6% in Gadsden County, with Gadsden County and Wakulla County below Leon County. Over 10 years of annual figures the share fell 7.8 points, from 26.9% in 2014 to 19.1% in 2023; its peak was 26.9% in 2014.

CDC also counts 169 tests taken after mitigation in Leon 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, Leon County against Florida2014 to 2023, years with 30 or more tests: Leon County 26.9% to 19.1%, the state's pooled share 18.5% in 2023.
Leon CountyFlorida, pooled
Share of reported tests at or above 4 pCi/L by year, Leon County against Florida: data table
YearTestsLeon County, at or above 4 pCi/LFlorida, pooled
201482626.9%25.7%
201583822.2%26.5%
20161,12717.7%24.3%
20171,20523.5%21.7%
201895622.1%23.5%
20191,14116.8%29.6%
20201,02723.5%23.2%
20211,27619.4%15.4%
20224,29616.4%22.8%
20231,19619.1%18.5%
Leon County against Florida, the United States and nearby counties, 2023
AreaTestsAt or above 4 pCi/LMedianDifference from Leon County
Leon County1,19619.1%1.8 pCi/LThis county
Florida, pooled49 counties, pooled16,58918.5%Not pooled−0.6 points
United States, pooled642 counties, pooled128,74033.4%Not pooled+14.3 points
Marion Countyhighest in the state18244.5%3.6 pCi/L+25.4 points
Clay Countylowest in the state360.0%1.0 pCi/L−19.1 points
Gadsden County, FLborders it9614.6%1.3 pCi/L−4.5 points
Wakulla County, FLborders it313.2%0.8 pCi/L−15.9 points
Jefferson County, FLborders it130.0%1.7 pCi/L−19.1 points
Where Leon County's reported results fell, 2023, beside Florida and the United States
ResultLeon County testsLeon County shareFlorida shareU.S. shareAgainst Florida
Under 2 pCi/L63352.9%57.3%41.4%−4.4 points
2 to 4 pCi/L33427.9%24.2%25.2%+3.7 points
4 pCi/L and above22919.1%18.5%33.4%+0.6 points
Leon County ranked among the 30 Florida counties with 30 or more tests, by share at or above 4 pCi/L, 2023
CountyRankTestsAt or above 4 pCi/LMedian
Miami-Dade County3 of 301,91939.6%2.8 pCi/L
Charlotte County4 of 309131.9%2.9 pCi/L
Collier County5 of 301,60722.7%2.3 pCi/L
Alachua County6 of 3065921.4%2.4 pCi/L
Lee County7 of 301,22420.3%2.2 pCi/L
Leon County8 of 301,19619.1%1.8 pCi/L
Gadsden County9 of 309614.6%1.3 pCi/L
Sarasota County10 of 3049612.3%1.6 pCi/L
Polk County11 of 3013611.0%1.1 pCi/L
Manatee County12 of 3026311.0%1.5 pCi/L
Orange County13 of 301,1079.5%0.9 pCi/L
Leon County radon tests by year, against Florida's pooled share
YearTestsAt or above 4 pCi/LMedianHighestFlorida, pooledChange from the row before
20231,19619.1%1.8 pCi/L16.7 pCi/L18.5%+2.7 points
20224,29616.4%1.8 pCi/L76.1 pCi/L22.8%−3.0 points
20211,27619.4%1.9 pCi/L76.0 pCi/L15.4%−4.1 points
20201,02723.5%2.0 pCi/L271.0 pCi/L23.2%+6.7 points
20191,14116.8%2.0 pCi/L37.0 pCi/L29.6%−5.3 points
201895622.1%2.1 pCi/L65.1 pCi/L23.5%−1.4 points
20171,20523.5%2.1 pCi/L42.0 pCi/L21.7%+5.8 points
20161,12717.7%1.9 pCi/L307.1 pCi/L24.3%−4.5 points
201583822.2%2.3 pCi/L20.7 pCi/L26.5%−4.7 points
201482626.9%2.4 pCi/L31.3 pCi/L25.7%First on file

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

Leon County, Geology

The ground under Leon County

Predicted

USGS's geologic map puts all of Leon County's mapped land in one class: low radon potential. The map puts 77.7% of Leon County in the area it calls Northern Highland and 22.3% in Gulf/Atlantic Lowland and Central Highland. USGS gives both a radon index of 6, in the low band (5 to 8).

USGS's geologic areas under Leon County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Northern HighlandSand, silt, clay, gravelLow677.7%
Gulf/Atlantic Lowland and Central Highlandsand, silt, clay, gravelLow622.3%

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

Leon County beside the ground around it

Across Florida 7.1% of the land is rated moderate; none of Leon County's is. None of the 6 counties that border it has any moderate-potential ground either.

Share of land by USGS radon potential: Leon County, the 6 counties bordering it and Florida
AreaEPA zoneLow potentialModerate potentialHigh potential
Leon CountyZone 2100%NoneNone
Jefferson CountyZone 399.9%NoneNone
Grady County, GAZone 3100%NoneNone
Wakulla CountyZone 397.0%NoneNone
Gadsden CountyZone 3100%NoneNone
Thomas County, GAZone 3100%NoneNone
Liberty CountyZone 3100%NoneNone
Florida67 counties, pooled by land areaVaries89.7%7.1%None

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

Local help

Leon County, Local resources

Radon testing and mitigation in Leon County

Listed radon businesses with an address in Leon County:

Listed radon professionals by town: Tallahassee

What Florida's program says
Phone
850-245-4288
Email
PHtoxicology@FLhealth.gov
Licensing of radon professionals
Florida Statutes require the certification of businesses and individuals providing radon services or any other radon related activity.

What it means

Leon County, Questions

Questions about radon in Leon County

Are radon levels high in Leon County?

In 2023, 19.1% of the radon tests reported to CDC for Leon County, Florida were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.8 pCi/L. Of 30 Florida counties with 30 or more tests for the same period, 7 reported a higher share; pooled, the state comes to 18.5%.

Which counties border Leon County?

Leon County borders 6 counties: Jefferson County, FL, Grady County, GA, Wakulla County, FL, Gadsden County, FL, Thomas County, GA and Liberty County, FL.

Products

Leon County, Products

Testing a home in Leon County

In Leon County, 19.1% of 1,196 tests reported to CDC in 2023 reached 4 pCi/L, against 18.5% pooled across Florida. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Leon County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Leon County homes, compared

Explore

Leon County, Bordering counties

Counties bordering Leon County

Calculated by Radon411

Leon County, Cities and towns

Cities and towns in Leon County

The Census Bureau estimates 299,048 residents in Leon County for July 1, 2025, 5,123 more than in 2020 (+1.7%). That works out to 447 people per square mile of land. Tallahassee, its one incorporated place, has 204,902 residents, 68.5% of the total. Testing is reported here more often than across the state: CDC's 1,196 reported tests for 2023 come to 4.0 for every 1,000 residents (2025 estimate), against 0.7 for Florida.

Tallahassee is the one incorporated place here; CDC publishes no figure by town, so it reads Leon County's.

Tallahassee, Leon County: residents on July 1, 2025
PlaceResidentsSince 2020Share of residents
Tallahassee204,902+3.5%68.5%

One incorporated place, 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).

Leon County, Homes

Homes in Leon County

Fewer than six in ten of Leon County's 135,906 homes are detached houses (49%, against 55% across Florida); the rest are attached, in shared buildings or mobile. Half of its homes were built before 1988, close to Florida's 1988: 9% date from before 1960 and 27% from 2000 or later. 52% of occupied homes are lived in by their owner (Florida: 67%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Leon County, Florida, 2019 to 2023
HomesLeon CountyFlorida
Housing units135,90610,082,356
Detached houses49%55%
In buildings of 5 or more26%25%
Mobile homes7%8%
Built before 19609%10%
Built since 200027%30%
Middle year built19881988
Owner-occupied52%67%

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