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Radon Levels in Putnam County, Florida

EPA puts Putnam County in Zone 3, its lowest radon zone, and only 10 radon tests from it are on file with CDC (2023). Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

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  • Share at 4+ pCi/L

    1.1%

    21.6 pts below FL

    Putnam
    1.1%
    Florida
    22.7%

    95 tests, 2008 to 2017

  • Median result

    0.1pCi/L

    Below action level

    Putnam
    0.1 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    95

    28th of 40 by tests

    Putnam
    95
    Collier
    20,308

    Reported to CDC before any fix, 2008 to 2017

  • 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

    38 of 40

    Lowest quarter

    Putnam
    1.1%
    Marion
    42.9%

    By share, of 40 with 30+ tests

Read a result for Putnam County

Starts at Putnam County's median, 0.1 pCi/L

0.2pCi/L

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

EPA’s reading of 0.2 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. 0.1 pCi/L above Putnam County's median of 0.1 pCi/L.

Interpret this reading

The data

Putnam County, At a glance

Putnam County at a glance

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

is EPA's lowest class, and its forecast for Putnam 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 Putnam County, 2023

Share of reported tests at or above 4 pCi/L, by year, Putnam County
Share of reported tests at or above 4 pCi/L, by year, Putnam County
YearShare of reported tests at or above 4 pCi/L
20140.0%
20150.0%
20170.0%
20190.0%
20210.0%
20230.0%

2023: 0.0%. Across these years the share ran from 0.0% to 0.0%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

Only 10 tests were reported to CDC for Putnam County over 2023, and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor 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

Putnam County, Compared

Putnam County radon figures, compared

Calculated by Radon411

Only 1 of 95 radon tests reported for Putnam County over the 2008 to 2017 laboratory totals reached 4 pCi/L (1.1%). The median result, 0.1 pCi/L, sits below 2, well under EPA's 4 pCi/L action level, and the top reported result was 4.2 pCi/L.

The newest figure, in 2023, counts only 10 tests (0.0% at or above 4 pCi/L), too few to compare, so this reading uses the 95-test figure.

Across 62 Florida counties pooled together, 22.7% of tests reached that level, so Putnam County runs 21.6 points below its state. Against the national pool of 35.7%, the gap is 34.6 points lower. Its place in the state: 38th of 40 Florida counties with 30 or more tests for the same period.

Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 1.1% share point the same way here. Of 4 neighbours with a figure, all 4 reported a larger share at or above 4 pCi/L; the spread is 1.8% (Volusia County) to 42.9% (Marion County).

Below the action level, 91 tests (95.8%) came in under 2 pCi/L, against 45.5% statewide, and 3 tests (3.2%) fell between 2 and 4, against 31.8% statewide. USGS geology rates 100% of the county's land low radon potential.

The busiest year on file was 2019, with 19 tests reported; the quietest, 2017, had 1.

Putnam County against Florida, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Putnam County
Putnam County951.1%0.1 pCi/LThis county
Florida, pooled62 counties, pooled53,79422.7%Not pooled+21.6 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+34.6 points
Polk Countyhighest in the state61728.4%2.1 pCi/L+27.3 points
St. Lucie Countylowest in the state460.0%0.1 pCi/L−1.1 points
Marion County, FLborders it90342.9%3.3 pCi/L+41.8 points
Alachua County, FLborders it2,16235.2%2.9 pCi/L+34.1 points
Clay County, FLborders it2313.0%1.2 pCi/L+11.9 points
St. Johns County, FLborders it506.0%0.7 pCi/L+4.9 points
Flagler County, FLborders it214.8%1.2 pCi/L+3.7 points
Volusia County, FLborders it4571.8%0.7 pCi/L+0.7 points
Bradford County, FLborders it50.0%2.0 pCi/L−1.1 points
Where Putnam County's reported results fell, 2008 to 2017, laboratory, beside Florida and the United States
ResultPutnam County testsPutnam County shareFlorida shareU.S. shareAgainst Florida
Under 2 pCi/L9195.8%45.5%39.6%+50.3 points
2 to 4 pCi/L33.2%31.8%24.7%−28.6 points
4 pCi/L and above11.1%22.7%35.7%−21.6 points
Putnam County ranked among the 40 Florida counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Brevard County30 of 408392.6%0.8 pCi/L
Indian River County31 of 401572.5%0.7 pCi/L
Nassau County32 of 40502.0%0.7 pCi/L
Santa Rosa County33 of 40512.0%0.8 pCi/L
Hernando County34 of 402231.8%0.8 pCi/L
Volusia County35 of 404571.8%0.7 pCi/L
Escambia County36 of 40651.5%0.9 pCi/L
Duval County37 of 404801.3%0.5 pCi/L
Putnam County38 of 40951.1%0.1 pCi/L
Osceola County39 of 402400.8%0.8 pCi/L
St. Lucie County40 of 40460.0%0.1 pCi/L
Putnam County radon tests by year, against Florida's pooled share
YearTestsAt or above 4 pCi/LMedianHighestFlorida, pooledChange from the row before
2023100.0%0.9 pCi/L1.8 pCi/L18.5%Level
2021130.0%0.7 pCi/L2.6 pCi/L15.4%Level
2019190.0%0.4 pCi/L2.2 pCi/L29.6%Level
201710.0%1.4 pCi/L1.4 pCi/L21.7%Level
201520.0%0.7 pCi/L0.8 pCi/L26.5%Level
201410.0%1.0 pCi/L1.0 pCi/L25.7%First on file

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

Putnam County, Geology

The ground under Putnam County

Predicted

USGS's geologic map puts all of Putnam 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 Putnam 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.

Putnam County beside the ground around it

Across Florida 7.1% of the land is rated moderate; none of Putnam County's is. Of the 7 counties that border it, 3 have more moderate-potential ground, Alachua County the most at 47.3%.

Share of land by USGS radon potential: Putnam County, the 7 counties bordering it and Florida
AreaEPA zoneLow potentialModerate potentialHigh potential
Putnam CountyZone 3100%NoneNone
Clay CountyZone 3100%NoneNone
Marion CountyZone 268.6%31.4%None
Flagler CountyZone 3100%NoneNone
St. Johns CountyZone 396.4%NoneNone
Alachua CountyZone 252.7%47.3%None
Bradford CountyZone 377.8%22.2%None
Volusia CountyZone 398.3%NoneNone
Florida67 counties, pooled by land areaVaries89.7%7.1%None

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

Local help

Putnam County, Local resources

Radon testing and mitigation in Putnam County

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

Putnam County, Questions

Questions about radon in Putnam County

Are radon levels high in Putnam County?

In 2023, 0.0% of the radon tests reported to CDC for Putnam County, Florida were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.9 pCi/L. Of 40 Florida counties with 30 or more tests for the same period, 37 reported a higher share; pooled, the state comes to 22.7%.

Which counties border Putnam County?

Putnam County borders 7 counties: Clay County, Marion County, Flagler County, St. Johns County, Alachua County, Bradford County and Volusia County.

Products

Putnam County, Products

Testing a home in Putnam County

In Putnam County, 1.1% of 95 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 22.7% 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 Putnam County.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Putnam County homes, compared

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Putnam County, Bordering counties

Counties bordering Putnam County

Calculated by Radon411

Putnam County, Cities and towns

Cities and towns in Putnam County

Putnam County is growing: the Census Bureau puts it at 77,734 residents on July 1, 2025, up 5.9% from 73,383 in 2020. That works out to 107 people per square mile of land. No town dominates: Palatka, the largest, has 10,872 residents, 14.0% of the total. Together its 5 incorporated places hold 20.2% of those residents; the other 79.8% live outside any of them. Reported testing is thin here: 95 tests over 2008 to 2017, or 1.2 for every 1,000 residents (2025 estimate), where Florida as a whole comes to 2.3.

From Palatka to Welaka, CDC publishes no figure by town: each reads Putnam County's.

The cities and towns in Putnam County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Palatka10,872+4.0%14.0%
Crescent City1,728+4.3%2.2%
Interlachen1,502+6.5%1.9%
Pomona Park824+5.8%1.1%
Welaka786+8.4%1.0%

5 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).

Putnam County, Homes

Homes in Putnam County

Mobile homes are 43% of Putnam County's 36,614 homes and detached houses 50%, against 55% across Florida. Half of its homes were built before 1984, close to Florida's 1988: 14% date from before 1960 and 21% from 2000 or later. 73% 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 Putnam County, Florida, 2019 to 2023
HomesPutnam CountyFlorida
Housing units36,61410,082,356
Detached houses50%55%
In buildings of 5 or more4%25%
Mobile homes43%8%
Built before 196014%10%
Built since 200021%30%
Middle year built19841988
Owner-occupied73%67%

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