Short-term kit
RA100 short-term liquid scintillation radon test kit
- Lab fee extra
Method: Liquid scintillation
In home: 48 to 96 hours
Locations and reports
Radon Levels in Madison County, Virginia
EPA puts Madison County in Zone 2, its middle radon zone, and high results are common there: 44.0% of the 184 radon tests reported to CDC (2008 to 2017, laboratory totals) came back 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
Share at 4+ pCi/L
44.0%
13.6 pts above VA
- Madison
- 44.0%
- Virginia
- 30.4%
184 tests, 2008 to 2017
Median result
3.5pCi/L
Below action level
- Madison
- 3.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
184
46th of 84 by tests
- Madison
- 184
- Fairfax
- 8,657
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Rank in Virginia
20 of 84
Top quarter
- Madison
- 44.0%
- Russell
- 67.3%
By share, of 84 with 30+ tests
Read a result for Madison County
Starts at Madison County's median, 3.5 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.5 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 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. Madison County's median reported result, 2008 to 2017.
The data
Madison County, At a glance
Madison County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Madison County is a
USGS geologic potential: Moderate across 99% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Madison County, 2008 to 2017, laboratory
Under 2 pCi/L: 31%2 to 4 pCi/L: 25%4 pCi/L and above: 44%
Of 184 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 57 | 31.0% |
| 2 to 4 pCi/L | 46 | 25.0% |
| 4 pCi/L and above | 81 | 44.0% |
What these figures count
These are the 184 tests reported to CDC for Madison County over 2008 to 2017 (laboratory totals), 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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Madison County, Compared
Madison County radon figures, compared
Calculated by Radon411In Madison County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (81 of 184) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 8.3 points higher. Across 131 Virginia counties pooled together, 30.4% of tests reached that level, so Madison County runs 13.6 points above its state.
Of 5 neighbours with a figure, none reported a larger share at or above 4 pCi/L; the spread is 34.6% (Greene County) to 41.6% (Rappahannock County). By share, Madison County is 20th of 84 Virginia counties with 30 or more tests for the same period.
Half the tests came in under 3.5 pCi/L and half over it; the single highest reached 99.3 pCi/L. Below the action level, 57 tests (31.0%) came in under 2 pCi/L, against 44.7% statewide, and 46 tests (25.0%) fell between 2 and 4, against 24.9% statewide.
Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 44.0% share point the same way here. USGS geology rates 99% of the county's land moderate radon potential. CDC also counts 17 tests taken after mitigation in Madison County for the same period: tests in homes where a fix was already in.
CDC's ten-year totals for Madison County went from 102 tests (2005 to 2014) to 184 (2008 to 2017), the share going from 46.1% to 44.0%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Madison County, Geology
The ground under Madison County
PredictedMost of the ground under Madison County is one class on USGS's geologic map: 99.5% of its land is moderate radon potential, with 0.5% high. The map puts 87.7% of Madison County in the area it calls Blue Ridge and 11.8% in Mesozoic Basins, with one smaller area beside them. USGS gives the first a radon index of 10 and the second 11, both in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Blue Ridge | Granite, pegmatite, monazite, schist, and gneiss. | Moderate | 10 | 87.7% |
| Mesozoic Basins | Sandstone, siltstone and lacustrine black shale. | Moderate | 11 | 11.8% |
| Inner Piedmont | Granite, pegmatites, granitic gneiss, schist and gneiss, slate, and phyllite. | High | 12 | 0.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Madison County beside the ground around it
Virginia as a whole has more high-potential ground than Madison County: 47.9% of its land, against 0.5% here. Of the 5 counties that border it, 3 have more high-potential ground, Orange County the most at 86.8%.
The map rates the ground, not the air in any home.
Local help
Madison County, Local resources
Radon testing and mitigation in Madison County
- VDH Radon ProgramVDH Radon Program answers questions about testing, mitigation and the rules in Virginia.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsAsk the program whether it has free or discounted kits, or compare kits you can buy.
- Compare kits
- Professionals in Virginia2 professionals are listed in Virginia.
What Virginia's program says
- Phone
- (804) 864-8161
- Radon@vdh.virginia.gov
- Licensing of radon professionals
The Code of Virginia requires that Radon testers and mitigators be currently certified by either the National Radon Proficiency Program (NRPP) or the National Radon Safety Board (NRSB).
What it means
Madison County, Questions
Questions about radon in Madison County
Are radon levels high in Madison County?
Over the 2008 to 2017 laboratory totals, 44.0% of the radon tests reported to CDC for Madison County, Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.5 pCi/L. Of 84 Virginia counties with 30 or more tests for the same period, 19 reported a higher share; pooled, the state comes to 30.4%.
Which counties border Madison County?
Madison County borders 5 counties: Greene County, Culpeper County, Page County, Orange County and Rappahannock County.
Products
Madison County, Products
Testing a home in Madison County
In Madison County, 44.0% of 184 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 30.4% pooled across Virginia. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Madison County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
MonitorAEGTEST
HOUND-3699 radon monitor with a 2.1-inch touchscreen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
First reading: Within 1 hour
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Madison County, Bordering counties
Counties bordering Madison County
Calculated by Radon411- Radon levels in Rappahannock CountyEPA zone 2
41.6%at or above 4 pCi/L
Median 3.3 pCi/L · 137 tests · 2.4 points below Madison County
- Radon levels in Culpeper CountyEPA zone 2
40.1%at or above 4 pCi/L
Median 3.2 pCi/L · 891 tests · 3.9 points below Madison County
- Radon levels in Page CountyEPA zone 1
38.3%at or above 4 pCi/L
Median 3.3 pCi/L · 141 tests · 5.7 points below Madison County
- Radon levels in Orange CountyEPA zone 1
36.1%at or above 4 pCi/L
Median 2.8 pCi/L · 462 tests · 7.9 points below Madison County
- Radon levels in Greene CountyEPA zone 2
34.6%at or above 4 pCi/L
Median 2.8 pCi/L · 214 tests · 9.4 points below Madison County
Madison County, Cities and towns
Cities and towns in Madison County
The Census Bureau estimates 14,237 residents in Madison County for July 1, 2025, 375 more than in 2020 (+2.7%). That works out to 44 people per square mile of land. Madison, its one incorporated place, has 211 residents, 1.5% of the total. Testing is reported here more often than across the state: CDC's 184 reported tests for 2008 to 2017 come to 12.9 for every 1,000 residents (2025 estimate), against 6.0 for Virginia.
Madison is the one incorporated place here; CDC publishes no figure by town, so it reads Madison County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Madison | 211 | +2.9% | 1.5% |
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).
Madison County, Homes
Homes in Madison County
Madison County is a place of houses on their own lots: 94% of its 6,110 homes are detached single-family houses, against 61% across Virginia. Half of its homes were built before 1980, close to Virginia's 1984: 26% date from before 1960 and 23% from 2000 or later. Owners live in 80% of the occupied homes (Virginia: 67%), so for most households a test and a fix are their own to order.
| Homes | Madison County | Virginia |
|---|---|---|
| Housing units | 6,110 | 3,654,784 |
| Detached houses | 94% | 61% |
| In buildings of 5 or more | 1% | 19% |
| Mobile homes | 3% | 4% |
| Built before 1960 | 26% | 19% |
| Built since 2000 | 23% | 25% |
| Middle year built | 1980 | 1984 |
| Owner-occupied | 80% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.