Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
Locations and reports
Radon Levels in Orange County, North Carolina
EPA puts Orange County in Zone 3, its lowest radon zone, and only 7 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
10.7%
11.9 pts below NC
- Orange
- 10.7%
- NC
- 22.6%
1,095 tests, 2008 to 2017
Median result
1.1pCi/L
Below action level
- Orange
- 1.1 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
1,095
15th of 75 by tests
- Orange
- 1,095
- Wake
- 9,694
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Rank in NC
51 of 75
Middle half
- Orange
- 10.7%
- Transylvania
- 47.8%
By share, of 75 with 30+ tests
Read a result for Orange County
Starts at Orange County's median, 1.1 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.1 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. Orange County's median reported result, 2008 to 2017.
The data
Orange County, At a glance
Orange 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 Orange County, 2022
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 10.2% |
| 2020 | 13.0% |
| 2021 | 10.6% |
| 2022 | 0.0% |
2022: 0.0%. Across these years the share ran from 0.0% to 13.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 7 tests were reported to CDC for Orange 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).
Orange County, Compared
Orange County radon figures, compared
Calculated by Radon411Orange County reports fewer high tests than North Carolina overall. 10.7% of its 1,095 tests over the 2008 to 2017 laboratory totals were at or above 4 pCi/L. That is 11.9 points below the 22.6% pooled from 99 North Carolina counties.
The newest figure, in 2022, counts only 7 tests (0.0% at or above 4 pCi/L), too few to compare, so this reading uses the 1,095-test figure.
Ordered from highest share down, it comes 51st of 75 North Carolina counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 35.7%; Orange County sits 25.0 points below it.
Next door, the shares run from 3.7% in Alamance County to 17.4% in Person County, with Durham County and Alamance County below Orange County. Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 10.7% share point the same way here.
Half the tests came in under 1.1 pCi/L and half over it; the single highest reached 26.8 pCi/L. The rest split 72.1% under 2 pCi/L and 17.3% from 2 to 4 (North Carolina: 55.6% and 21.8%). Year by year, 2014 opened at 10.2% and 2021 closed at 10.6% (about level), with 2020 the high at 13.0%.
The busiest year on file was 2014, with 166 tests reported; the quietest, 2022, had 7.
Orange CountyNorth Carolina, pooled
| Year | Tests | Orange County, at or above 4 pCi/L | North Carolina, pooled |
|---|---|---|---|
| 2014 | 166 | 10.2% | 21.9% |
| 2020 | 161 | 13.0% | 21.1% |
| 2021 | 94 | 10.6% | 14.9% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Orange County, Geology
The ground under Orange County
PredictedUSGS's geologic map puts all of Orange County's mapped land in one class: low radon potential. The map puts 93.6% of Orange County in the area it calls Carolina Slate Belt and 6.4% in Sanford-Durham Sub-Basins. USGS gives the first a radon index of 6 and the second 8, both in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Carolina Slate Belt | Felsic metavolcanics, intermediate volcanics, metamudstone, argillite, and epiclastic rocks. | Low | 6 | 93.6% |
| Sanford-Durham Sub-Basins | Arkosic sandstone, siltstone and conglomerate. | Low | 8 | 6.4% |
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 North Carolina 1.3% of the land is rated high; none of Orange County's is. Of the 5 counties that border it, 4 have more moderate-potential ground, Caswell County the most at 65.4%.
The map rates the ground, not the air in any home.
Local help
Orange County, Local resources
Radon testing and mitigation in Orange 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.
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
Orange County, Questions
Questions about radon in Orange County
Are radon levels high in Orange County?
In 2022, 0.0% of the radon tests reported to CDC for Orange County, North Carolina were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.1 pCi/L. Of 75 North Carolina counties with 30 or more tests for the same period, 50 reported a higher share; pooled, the state comes to 22.6%.
Which counties border Orange County?
Orange County borders 5 counties: Durham County, Alamance County, Chatham County, Person County and Caswell County.
Products
Orange County, Products
Testing a home in Orange County
In Orange County, 10.7% of 1,095 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 22.6% pooled across North Carolina. 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
Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
MonitorAranet
Radon One battery digital radon monitor with an e-ink screen
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- Alarm
- Screen, app
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
Orange County, Bordering counties
Counties bordering Orange County
Calculated by Radon411- Radon levels in Person CountyEPA zone 3
17.4%at or above 4 pCi/L
Median 1.3 pCi/L · 190 tests · 6.7 points above Orange County
- Radon levels in Caswell CountyEPA zone 2
14.9%at or above 4 pCi/L
Median 1.6 pCi/L · 47 tests · 4.2 points above Orange County
- Radon levels in Chatham CountyEPA zone 3
10.9%at or above 4 pCi/L
Median 1.1 pCi/L · 587 tests · 0.2 points above Orange County
- Radon levels in Durham CountyEPA zone 3
4.3%at or above 4 pCi/L
Median 0.7 pCi/L · 1,570 tests · 6.4 points below Orange County
- Radon levels in Alamance CountyEPA zone 3
3.7%at or above 4 pCi/L
Median 0.5 pCi/L · 520 tests · 7.0 points below Orange County
Orange County, Cities and towns
Cities and towns in Orange County
Orange County is growing: the Census Bureau puts it at 152,498 residents on July 1, 2025, up 6.1% from 143,748 in 2020. That works out to 384 people per square mile of land. Durham, the largest place on its list (305,561 residents in all), extends beyond Orange County, so no share of the total is worked out for it. CDC's 1,095 reported tests for 2008 to 2017 work out to 7.2 per 1,000 residents (2025 estimate), close to North Carolina's 6.5.
From Durham to Hillsborough, CDC publishes no figure by town: each reads Orange County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Durhamextends beyond Orange County | 305,561 | +8.5% | Counted whole |
| Chapel Hillextends beyond Orange County | 63,565 | +11.4% | Counted whole |
| Mebaneextends beyond Orange County | 21,952 | +20.3% | Counted whole |
| Carrboro | 20,962 | −1.5% | 13.7% |
| Hillsborough | 9,778 | +1.3% | 6.4% |
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). A place that extends beyond Orange County is counted whole, so it has no share.
Orange County, Homes
Homes in Orange County
Of Orange County's 62,127 homes, 60% are detached houses, against 65% across North Carolina; 22% are in buildings of five or more homes. Half of its homes were built before 1989, close to North Carolina's 1990: 12% date from before 1960 and 31% from 2000 or later. 64% 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 | Orange County | North Carolina |
|---|---|---|
| Housing units | 62,127 | 4,815,195 |
| Detached houses | 60% | 65% |
| In buildings of 5 or more | 22% | 14% |
| Mobile homes | 6% | 11% |
| Built before 1960 | 12% | 14% |
| Built since 2000 | 31% | 33% |
| Middle year built | 1989 | 1990 |
| Owner-occupied | 64% | 66% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.