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
Locations and reports
Radon Levels in Henderson County, North Carolina
EPA puts Henderson County in Zone 1, its highest radon zone, and only 10 radon tests from it are on file with CDC (2022). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
42.6%
19.4 pts above NC
- Henderson
- 42.6%
- NC
- 23.2%
4,126 tests, 2007 to 2016
Median result
3.3pCi/L
Below action level
- Henderson
- 3.3 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2007 to 2016
Tests reported
4,126
5th of 73 by tests
- Henderson
- 4,126
- Wake
- 9,664
Reported to CDC before any fix, 2007 to 2016
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in NC
6 of 73
Top quarter
- Henderson
- 42.6%
- Transylvania
- 48.1%
By share, of 73 with 30+ tests
Read a result for Henderson County
Starts at Henderson County's median, 3.3 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.3 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. Henderson County's median reported result, 2007 to 2016.
The data
Henderson County, At a glance
Henderson County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Henderson County in
USGS geologic potential: High across 53% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Henderson County, 2022
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 41.7% |
| 2020 | 35.6% |
| 2021 | 28.6% |
| 2022 | 40.0% |
2022: 40.0%. Across these years the share ran from 28.6% to 41.7%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 10 tests were reported to CDC for Henderson County over 2022, 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: 2022. Measured data period: 2005 to 2022 (every CDC figure on file).
Henderson County, Compared
Henderson County radon figures, compared
Calculated by Radon411In Henderson County, about 4 in 10 reported tests over the 2007 to 2016 laboratory totals (1,758 of 4,126) were at or above EPA's action level. Against the national pool of 35.8%, the gap is 6.8 points higher. Across 99 North Carolina counties pooled together, 23.2% of tests reached that level, so Henderson County runs 19.4 points above its state.
The newest figure, in 2022, counts only 10 tests (40.0% at or above 4 pCi/L), too few to compare, so this reading uses the 4,126-test figure.
Of 6 neighbours with a figure, 1 reported a larger share at or above 4 pCi/L and 5 a smaller one; the spread is 19.9% (Greenville County, SC) to 48.1% (Transylvania County). By share, Henderson County is 6th of 73 North Carolina counties with 30 or more tests for the same period.
Year by year, 2014 opened at 41.7% and 2021 closed at 28.6% (down 13.1 points), with 2014 the high at 41.7%. Half the tests came in under 3.3 pCi/L and half over it; the single highest reached 196.0 pCi/L. Below the action level, 1,249 tests (30.3%) came in under 2 pCi/L, against 55.2% statewide, and 1,119 tests (27.1%) fell between 2 and 4, against 21.6% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 42.6% share point the same way here. USGS geology rates 53% of the county's land high radon potential. CDC also counts 437 tests taken after mitigation in Henderson County for the same period: tests in homes where a fix was already in.
The busiest year on file was 2014, with 827 tests reported; the quietest, 2022, had 10.
Henderson CountyNorth Carolina, pooled
28.6% % of tests14.9% % of tests
| Year | Tests | Henderson County, at or above 4 pCi/L | North Carolina, pooled |
|---|---|---|---|
| 2014 | 827 | 41.7% | 21.9% |
| 2020 | 641 | 35.6% | 21.1% |
| 2021 | 451 | 28.6% | 14.9% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Henderson County, Geology
The ground under Henderson County
PredictedUSGS's geologic map splits Henderson County: 52.6% of its land is high radon potential and 47.4% moderate. The map puts 45.0% of Henderson County in the area it calls Chauga Belt and 35.7% in Inner Piedmont Belt, with 2 smaller areas beside them. USGS gives the first a radon index of 12, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Chauga Belt | Monzonitic to granodioritic gneiss. | High | 12 | 45.0% |
| Inner Piedmont Belt | Proterozoic through Cambrian biotite gneiss and schist, and mica schist. | Moderate | 11 | 35.7% |
| Blue Ridge | Granite, pegmatite, monazite, schist, and gneiss. | Moderate | 10 | 11.7% |
| Brevard Fault Zone | Schist, marble and phyllonite. | High | 12 | 7.6% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Henderson County beside the ground around it
Henderson County has more high-potential ground than North Carolina as a whole: 52.6% of its land against 1.3%. Of the 6 counties that border it, none has as large a share of high-potential ground; Transylvania County comes nearest at 52.0%.
The map rates the ground, not the air in any home.
Local help
Henderson County, Local resources
Radon testing and mitigation in Henderson County
Listed radon businesses with an address in Henderson County:
- North Carolina Radon ProgramNorth Carolina Radon Program, run by NCDHHS, answers questions about testing, mitigation and the rules in North Carolina.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 North Carolina2 professionals are listed in North Carolina.
Listed radon professionals by town: Mills River
What North Carolina's program says
- Licensing of radon professionals
The North Carolina Radon Program is presently developing a Radon Proficiency Program as directed by Session Law 2023-91 House Bill 782 .
What it means
Henderson County, Questions
Questions about radon in Henderson County
Are radon levels high in Henderson County?
In 2022, 40.0% of the radon tests reported to CDC for Henderson County, North Carolina were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.0 pCi/L. Of 73 North Carolina counties with 30 or more tests for the same period, 5 reported a higher share; pooled, the state comes to 23.2%.
Which counties border Henderson County?
Henderson County borders 6 counties: Polk County, NC, Transylvania County, NC, Buncombe County, NC, Rutherford County, NC, Haywood County, NC and Greenville County, SC.
Products
Henderson County, Products
Testing a home in Henderson County
In Henderson County, 42.6% of 4,126 tests reported to CDC over the 2007 to 2016 laboratory totals reached 4 pCi/L, against 23.2% pooled across North Carolina. In Zone 1 the year-round level in Henderson County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.
Test kits and monitors3
See every kit and monitor
MonitorKidde
Radon Detector (RAB) battery digital radon detector with an alarm
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 12 hours
Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Henderson County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Henderson County
Explore
Henderson County, Bordering counties
Counties bordering Henderson County
Calculated by Radon411- Radon levels in Transylvania County, NCEPA zone 1
48.1%at or above 4 pCi/L
Median 3.7 pCi/L · 3,996 tests · 5.5 points above Henderson County
- Radon levels in Polk County, NCEPA zone 2
31.2%at or above 4 pCi/L
Median 2.4 pCi/L · 616 tests · 11.4 points below Henderson County
- Radon levels in Buncombe County, NCEPA zone 1
30.3%at or above 4 pCi/L
Median 2.4 pCi/L · 6,670 tests · 12.3 points below Henderson County
- Radon levels in Haywood County, NCEPA zone 2
30.2%at or above 4 pCi/L
Median 2.2 pCi/L · 1,951 tests · 12.4 points below Henderson County
- Radon levels in Rutherford County, NCEPA zone 2
26.6%at or above 4 pCi/L
Median 2.4 pCi/L · 481 tests · 16.0 points below Henderson County
- Radon levels in Greenville County, SCEPA zone 1
19.9%at or above 4 pCi/L
Median 1.8 pCi/L · 11,402 tests · 22.7 points below Henderson County
Henderson County, Cities and towns
Cities and towns in Henderson County
The Census Bureau estimates 122,375 residents in Henderson County for July 1, 2025, 5,811 more than in 2020 (+5.0%). That works out to 328 people per square mile of land. No town dominates: Hendersonville, the largest, has 15,867 residents, 13.0% of the total. Testing is reported here more often than across the state: CDC's 4,126 reported tests for 2007 to 2016 come to 33.7 for every 1,000 residents (2025 estimate), against 6.3 for North Carolina.
From Hendersonville to Saluda, CDC publishes no figure by town: each reads Henderson County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Hendersonville | 15,867 | +4.3% | 13.0% |
| Fletcher | 8,373 | +5.0% | 6.8% |
| Mills River | 7,504 | +5.2% | 6.1% |
| Flat Rock | 3,643 | +4.6% | 3.0% |
| Laurel Park | 2,360 | +5.0% | 1.9% |
| Saludaextends beyond Henderson County | 671 | +6.3% | Counted whole |
Places in Henderson County with a city page: 1 of 1
6 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). A place that extends beyond Henderson County is counted whole, so it has no share.
Henderson County, Homes
Homes in Henderson County
Of Henderson County's 57,338 homes, 69% are detached houses, against 65% across North Carolina; 15% are mobile homes. Half of its homes were built before 1989, close to North Carolina's 1990: 14% date from before 1960 and 30% from 2000 or later. 74% of occupied homes are lived in by their owner (North Carolina: 66%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Henderson County | North Carolina |
|---|---|---|
| Housing units | 57,338 | 4,815,195 |
| Detached houses | 69% | 65% |
| In buildings of 5 or more | 6% | 14% |
| Mobile homes | 15% | 11% |
| Built before 1960 | 14% | 14% |
| Built since 2000 | 30% | 33% |
| Middle year built | 1989 | 1990 |
| Owner-occupied | 74% | 66% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.