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Radon Levels in Orange County, Florida

EPA puts Orange County in Zone 3, its lowest radon zone, and most reported tests there come back low, though 9.5% of 1,107 (2023) reached 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

    9.5%

    9.0 pts below FL

    Orange
    9.5%
    Florida
    18.5%

    1,107 tests, 2023

  • Median result

    0.9pCi/L

    Below action level

    Orange
    0.9 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2023

  • Tests reported

    1,107

    7th of 30 by tests

    Orange
    1,107
    Broward
    2,165

    Reported to CDC before any fix, 2023

  • EPA radon zone

    Zone 3

    Lower potential

    1. 1
    2. 2
    3. Zone 3

    1 highest, 3 lowest

    EPA predicts under 2 pCi/L indoors

  • Rank in Florida

    13 of 30

    Middle half

    Orange
    9.5%
    Marion
    44.5%

    By share, of 30 with 30+ tests

Read a result for Orange County

Starts at Orange County's median, 0.9 pCi/L

0.9pCi/L

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

EPA’s reading of 0.9 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. Orange County's median reported result, 2023.

Interpret this reading

The data

Orange County, At a glance

Orange County at a glance

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

is EPA's lowest class, and its forecast for Orange County as a whole is an average indoor of less than 2 pCi/L (less than 75 Bq/m³). A low zone clears no address in it: homes above EPA's turn up in all three zones.

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 Orange County, 2023

Share of reported tests at or above 4 pCi/L, by year, Orange County
Share of reported tests at or above 4 pCi/L, by year, Orange County
YearShare of reported tests at or above 4 pCi/L
20144.1%
20154.4%
20161.9%
20175.6%
201823.3%
20192.6%
20202.9%
20210.7%
20227.1%
20239.5%

2023: 9.5%. Across these years the share ran from 0.7% to 23.3%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 1,107 tests reported to CDC for Orange 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

Orange County, Compared

Orange County radon figures, compared

Calculated by Radon411

Orange County reports fewer high tests than Florida overall. 9.5% of its 1,107 tests in 2023 were at or above 4 pCi/L. That is 9.0 points below the 18.5% pooled from 49 Florida counties.

Ordered from highest share down, it comes 13th of 30 Florida counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 33.4%; Orange County sits 23.9 points below it.

Next door, the shares run from 0.0% in Brevard County to 11.0% in Polk County, with Seminole County, Osceola County and Volusia County below Orange County. Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 9.5% share point the same way here.

Half the tests came in under 0.9 pCi/L and half over it; the single highest reached 10.4 pCi/L. The rest split 78.7% under 2 pCi/L and 11.8% from 2 to 4 (Florida: 57.3% and 24.2%). Year by year, 2014 opened at 4.1% and 2023 closed at 9.5% (up 5.4 points), with 2018 the high at 23.3%.

The busiest year on file was 2022, with 3,069 tests reported; the quietest, 2014, had 410.

Share of reported tests at or above 4 pCi/L by year, Orange County against Florida2014 to 2023, years with 30 or more tests: Orange County 4.1% to 9.5%, the state's pooled share 18.5% in 2023.
Orange CountyFlorida, pooled
Share of reported tests at or above 4 pCi/L by year, Orange County against Florida: data table
YearTestsOrange County, at or above 4 pCi/LFlorida, pooled
20144104.1%25.7%
20155404.4%26.5%
20164241.9%24.3%
20178785.6%21.7%
20181,40223.3%23.5%
20194542.6%29.6%
20204822.9%23.2%
20211,1090.7%15.4%
20223,0697.1%22.8%
20231,1079.5%18.5%
Orange County against Florida, the United States and nearby counties, 2023
AreaTestsAt or above 4 pCi/LMedianDifference from Orange County
Orange County1,1079.5%0.9 pCi/LThis county
Florida, pooled49 counties, pooled16,58918.5%Not pooled+9.0 points
United States, pooled642 counties, pooled128,74033.4%Not pooled+23.9 points
Marion Countyhighest in the state18244.5%3.6 pCi/L+35.0 points
Clay Countylowest in the state360.0%1.0 pCi/L−9.5 points
Polk County, FLborders it13611.0%1.1 pCi/L+1.5 points
Seminole County, FLborders it1901.6%0.6 pCi/L−7.9 points
Osceola County, FLborders it701.4%1.2 pCi/L−8.1 points
Volusia County, FLborders it1631.2%0.6 pCi/L−8.3 points
Lake County, FLborders it1590.0%0.6 pCi/L−9.5 points
Brevard County, FLborders it2050.0%0.7 pCi/L−9.5 points
Where Orange County's reported results fell, 2023, beside Florida and the United States
ResultOrange County testsOrange County shareFlorida shareU.S. shareAgainst Florida
Under 2 pCi/L87178.7%57.3%41.4%+21.4 points
2 to 4 pCi/L13111.8%24.2%25.2%−12.4 points
4 pCi/L and above1059.5%18.5%33.4%−9.0 points
Orange 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
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
Broward County14 of 302,1659.4%1.7 pCi/L
Hillsborough County15 of 309847.5%0.9 pCi/L
Duval County16 of 307926.2%0.4 pCi/L
Pinellas County17 of 305595.9%1.2 pCi/L
Wakulla County18 of 30313.2%0.8 pCi/L
Orange County radon tests by year, against Florida's pooled share
YearTestsAt or above 4 pCi/LMedianHighestFlorida, pooledChange from the row before
20231,1079.5%0.9 pCi/L10.4 pCi/L18.5%+2.4 points
20223,0697.1%1.0 pCi/L14.6 pCi/L22.8%+6.4 points
20211,1090.7%1.0 pCi/L4.8 pCi/L15.4%−2.2 points
20204822.9%0.9 pCi/L13.7 pCi/L23.2%+0.3 points
20194542.6%0.6 pCi/L9.9 pCi/L29.6%−20.7 points
20181,40223.3%2.5 pCi/L53.0 pCi/L23.5%+17.7 points
20178785.6%0.9 pCi/L54.0 pCi/L21.7%+3.7 points
20164241.9%0.9 pCi/L9.7 pCi/L24.3%−2.5 points
20155404.4%0.9 pCi/L10.3 pCi/L26.5%+0.3 points
20144104.1%0.8 pCi/L11.8 pCi/L25.7%First on file

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

Orange County, Geology

The ground under Orange County

Predicted

USGS's geologic map puts all of Orange County's mapped land in one class: low radon potential. All of it lies in the area the map calls Gulf/Atlantic Lowland and Central Highland, to which USGS gives a radon index of 6, in the low band (5 to 8).

USGS's geologic areas under Orange County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Gulf/Atlantic Lowland and Central Highlandsand, silt, clay, gravelLow6100%

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

Orange County beside the ground around it

Across Florida 7.1% of the land is rated moderate; none of Orange County's is. Of the 6 counties that border it, 1 has more moderate-potential ground, Polk County the most at 33.7%.

Share of land by USGS radon potential: Orange County, the 6 counties bordering it and Florida
AreaEPA zoneLow potentialModerate potentialHigh potential
Orange CountyZone 3100%NoneNone
Seminole CountyZone 3100%NoneNone
Lake CountyZone 3100%NoneNone
Volusia CountyZone 398.3%NoneNone
Brevard CountyZone 382.5%NoneNone
Osceola CountyZone 3100%NoneNone
Polk CountyZone 266.3%33.7%None
Florida67 counties, pooled by land areaVaries89.7%7.1%None

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

Local help

Orange County, Local resources

Radon testing and mitigation in Orange County

Listed radon businesses with an address in Orange County:

Listed radon professionals by town: Orlando, Apopka, Winter Garden, Winter Park

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

Orange County, Questions

Questions about radon in Orange County

Are radon levels high in Orange County?

In 2023, 9.5% of the radon tests reported to CDC for Orange County, Florida were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.9 pCi/L. Of 30 Florida counties with 30 or more tests for the same period, 12 reported a higher share; pooled, the state comes to 18.5%.

Which counties border Orange County?

Orange County borders 6 counties: Seminole County, Lake County, Volusia County, Brevard County, Osceola County and Polk County.

Products

Orange County, Products

Testing a home in Orange County

In Orange County, 9.5% of 1,107 tests reported to CDC in 2023 reached 4 pCi/L, against 18.5% pooled across Florida. Zone 3 is the lowest label, yet homes at or above 4 pCi/L occur in every zone: a short-term kit (2 to 90 days) is the quick first check in Orange County.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Orange County homes, compared

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Orange County, Bordering counties

Counties bordering Orange County

Calculated by Radon411

Orange County, Cities and towns

Cities and towns in Orange County

Orange County is growing: the Census Bureau puts it at 1,528,002 residents on July 1, 2025, up 6.7% from 1,431,608 in 2020. Packed into its land, that is 1,694 people per square mile. Its largest town, Orlando, has 333,888 residents, 21.9% of the total. Together its 13 incorporated places hold 37.3% of those residents; the other 62.7% live outside any of them. CDC's 1,107 reported tests for 2023 work out to 0.7 per 1,000 residents (2025 estimate), close to Florida's 0.7.

From Orlando to Bay Lake, CDC publishes no figure by town: each reads Orange County's.

The 12 largest cities and towns in Orange County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Orlando333,888+8.3%21.9%
Apopka65,552+19.4%4.3%
Ocoee51,932+9.3%3.4%
Winter Garden48,063+1.2%3.1%
Winter Park30,444+1.4%2.0%
Maitland19,511Level1.3%
Belle Isle7,688+5.6%0.5%
Oakland3,774+6.1%0.2%
Windermere3,344+5.8%0.2%
Edgewood2,845+5.7%0.2%
Eatonville2,333+0.3%0.2%
Lake Buena Vista25−3.8%Under 0.1%
  • Bay Lake

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).

Orange County, Homes

Homes in Orange County

Fewer than six in ten of Orange County's 576,450 homes are detached houses (54%, against 55% across Florida); the rest are attached, in shared buildings or mobile. Half of its homes were built before 1993, close to Florida's 1988: 9% date from before 1960 and 38% from 2000 or later. 57% 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 Orange County, Florida, 2019 to 2023
HomesOrange CountyFlorida
Housing units576,45010,082,356
Detached houses54%55%
In buildings of 5 or more29%25%
Mobile homes3%8%
Built before 19609%10%
Built since 200038%30%
Middle year built19931988
Owner-occupied57%67%

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