Short-term kit
RA400 short-term liquid scintillation radon test kit, lab fee included
- Lab fee included
Method: Liquid scintillation
In home: 48 to 96 hours
Locations and reports
Radon Levels in Jefferson County, Florida
EPA puts Jefferson County in Zone 3, its lowest radon zone, and only 13 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
Share at 4+ pCi/L
11.1%
11.7 pts below FL
- Jefferson
- 11.1%
- Florida
- 22.8%
54 tests, 2022
Median result
1.9pCi/L
Below action level
- Jefferson
- 1.9 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2022
Tests reported
54
35th of 40 by tests
- Jefferson
- 54
- Miami-Dade
- 9,033
Reported to CDC before any fix, 2022
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Rank in Florida
17 of 40
Middle half
- Jefferson
- 11.1%
- Palm Beach
- 54.7%
By share, of 40 with 30+ tests
Read a result for Jefferson County
Starts at Jefferson County's median, 1.9 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.9 pCi/L
Below 2 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is below 2 pCi/L, the level at which EPA says a fix should be considered. Jefferson County's median reported result, 2022.
The data
Jefferson County, At a glance
Jefferson County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
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 Jefferson County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 0.0% |
| 2015 | 14.3% |
| 2016 | 0.0% |
| 2017 | 11.1% |
| 2018 | 12.0% |
| 2019 | 0.0% |
| 2020 | 12.5% |
| 2021 | 14.3% |
| 2022 | 11.1% |
| 2023 | 0.0% |
2023: 0.0%. Across these years the share ran from 0.0% to 14.3%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 13 tests were reported to CDC for Jefferson 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).
Jefferson County, Compared
Jefferson County radon figures, compared
Calculated by Radon411Jefferson County reports fewer high tests than Florida overall. 11.1% of its 54 tests in 2022 were at or above 4 pCi/L. That is 11.7 points below the 22.8% pooled from 54 Florida counties.
The newest figure, in 2023, counts only 13 tests (0.0% at or above 4 pCi/L), too few to compare, so this reading uses the 54-test figure.
Ordered from highest share down, it comes 17th of 40 Florida counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 23.9%; Jefferson County sits 12.8 points below it.
Next door, the shares run from 0.0% in Madison County to 16.4% in Leon County, with Wakulla County and Madison County below Jefferson County. Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 11.1% share point the same way here.
Half the tests came in under 1.9 pCi/L and half over it; the single highest reached 7.7 pCi/L. The rest split 50.0% under 2 pCi/L and 38.9% from 2 to 4 (Florida: 52.6% and 24.6%).
The busiest year on file was 2022, with 54 tests reported; the quietest, 2016, had 6.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Jefferson County, Geology
The ground under Jefferson County
PredictedUSGS's geologic map puts all of Jefferson County's mapped land in one class: low radon potential. The map puts 68.5% of Jefferson County in the area it calls Northern Highland and 31.3% in Gulf/Atlantic Lowland and Central Highland. USGS gives both a radon index of 6, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Northern Highland | Sand, silt, clay, gravel | Low | 6 | 68.5% |
| Gulf/Atlantic Lowland and Central Highland | sand, silt, clay, gravel | Low | 6 | 31.3% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Jefferson County beside the ground around it
Across Florida 7.1% of the land is rated moderate; none of Jefferson County's is. None of the 6 counties that border it has any moderate-potential ground either.
The map rates the ground, not the air in any home.
Local help
Jefferson County, Local resources
Radon testing and mitigation in Jefferson County
- Florida’s Radon ProgramFlorida’s Radon Program, run by Florida Department of Health, licenses or certifies radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in Florida.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Protect your family by requesting a FREE radon test kit.
- Compare kits
- Professionals in Florida77 professionals are listed in Florida.
What Florida's program says
- Phone
- 850-245-4288
- 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
Jefferson County, Questions
Questions about radon in Jefferson County
Are radon levels high in Jefferson County?
In 2023, 0.0% of the radon tests reported to CDC for Jefferson County, Florida were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.7 pCi/L. Of 40 Florida counties with 30 or more tests for the same period, 16 reported a higher share; pooled, the state comes to 22.8%.
Which counties border Jefferson County?
Jefferson County borders 6 counties: Leon County, FL, Madison County, FL, Thomas County, GA, Wakulla County, FL, Taylor County, FL and Brooks County, GA.
Products
Jefferson County, Products
Testing a home in Jefferson County
In Jefferson County, 11.1% of 54 tests reported to CDC in 2022 reached 4 pCi/L, against 22.8% 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 Jefferson County.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
MonitorAEGTEST
HOUND-3786 rechargeable radon monitor with a 3.5-inch color screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Ion chamber
First reading: Within 10 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Jefferson County, Bordering counties
Counties bordering Jefferson County
Calculated by Radon411- Radon levels in Leon County, FLEPA zone 2
16.4%at or above 4 pCi/L
Median 1.8 pCi/L · 4,296 tests · 5.3 points above Jefferson County
- Radon levels in Wakulla County, FLEPA zone 3
10.5%at or above 4 pCi/L
Median 1.6 pCi/L · 57 tests · 0.6 points below Jefferson County
- Radon levels in Madison County, FLEPA zone 3
0.0%at or above 4 pCi/L
Median 0.3 pCi/L · 45 tests · 11.1 points below Jefferson County
- Radon levels in Taylor County, FLEPA zone 3
0.0%at or above 4 pCi/L
Median 1.5 pCi/L · 3 tests · 11.1 points below Jefferson County
- Radon levels in Thomas County, GAEPA zone 3
No CDC figure for 2022; its page reads it against its own neighbours.
- Radon levels in Brooks County, GAEPA zone 3
No CDC figure for 2022; its page reads it against its own neighbours.
Jefferson County, Cities and towns
Cities and towns in Jefferson County
Jefferson County is growing: the Census Bureau puts it at 16,007 residents on July 1, 2025, up 11.1% from 14,403 in 2020. That works out to 27 people per square mile of land. Monticello, its one incorporated place, has 2,767 residents, 17.3% of the total. CDC's 54 reported tests for 2022 work out to 3.4 per 1,000 residents (2025 estimate), close to Florida's 2.6.
Monticello is the one incorporated place here; CDC publishes no figure by town, so it reads Jefferson County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Monticello | 2,767 | +6.7% | 17.3% |
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).
Jefferson County, Homes
Homes in Jefferson County
Of Jefferson County's 6,815 homes, 60% are detached houses, against 55% across Florida; 34% are mobile homes. Half of its homes were built before 1988, close to Florida's 1988: 14% date from before 1960 and 28% from 2000 or later. Owners live in 75% of the occupied homes (Florida: 67%), so for most households a test and a fix are their own to order.
| Homes | Jefferson County | Florida |
|---|---|---|
| Housing units | 6,815 | 10,082,356 |
| Detached houses | 60% | 55% |
| In buildings of 5 or more | 3% | 25% |
| Mobile homes | 34% | 8% |
| Built before 1960 | 14% | 10% |
| Built since 2000 | 28% | 30% |
| Middle year built | 1988 | 1988 |
| Owner-occupied | 75% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.