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 Caroline County, Virginia
EPA puts Caroline County in Zone 3, its lowest radon zone, and 32.7% of its 199 reported radon tests (2008 to 2017, laboratory totals) were 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
32.7%
2.3 pts above VA
- Caroline
- 32.7%
- Virginia
- 30.4%
199 tests, 2008 to 2017
Median result
2.5pCi/L
Below action level
- Caroline
- 2.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
199
44th of 84 by tests
- Caroline
- 199
- Fairfax
- 8,657
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 Virginia
48 of 84
Middle half
- Caroline
- 32.7%
- Russell
- 67.3%
By share, of 84 with 30+ tests
Read a result for Caroline County
Starts at Caroline County's median, 2.5 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.5 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. Caroline County's median reported result, 2008 to 2017.
The data
Caroline County, At a glance
Caroline County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 90% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Caroline County, 2008 to 2017, laboratory
Under 2 pCi/L: 38%2 to 4 pCi/L: 29%4 pCi/L and above: 33%
Of 199 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 75 | 37.7% |
| 2 to 4 pCi/L | 59 | 29.6% |
| 4 pCi/L and above | 65 | 32.7% |
What these figures count
These are the 199 tests reported to CDC for Caroline 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).
Caroline County, Compared
Caroline County radon figures, compared
Calculated by Radon411In Caroline County, about 3 in 10 reported tests over the 2008 to 2017 laboratory totals (65 of 199) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 3.0 points lower. Across 131 Virginia counties pooled together, 30.4% of tests reached that level, so Caroline County runs 2.3 points above its state.
Of 4 neighbours with a figure, 2 reported a larger share at or above 4 pCi/L and 2 a smaller one; the spread is 23.0% (Hanover County) to 45.5% (King George County). By share, Caroline County is 48th of 84 Virginia counties with 30 or more tests for the same period.
Half the tests came in under 2.5 pCi/L and half over it; the single highest reached 18.2 pCi/L. Below the action level, 75 tests (37.7%) came in under 2 pCi/L, against 44.7% statewide, and 59 tests (29.6%) fell between 2 and 4, against 24.9% statewide.
The reported tests do not follow EPA's Zone 3 label for Caroline County (predicted average under 2 pCi/L): 32.7% of them reached 4 pCi/L, more than a low-potential zone suggests. USGS geology rates 90% of the county's land low radon potential. CDC also counts 22 tests taken after mitigation in Caroline County for the same period: tests in homes where a fix was already in.
CDC's ten-year totals for Caroline County went from 103 tests (2005 to 2014) to 199 (2008 to 2017), the share going from 34.0% to 32.7%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Caroline County, Geology
The ground under Caroline County
PredictedMost of the ground under Caroline County is one class on USGS's geologic map: 90.1% of its land is low radon potential, with 9.5% high. The map puts 90.1% of Caroline County in the area it calls Tertiary Coastal Plain Sediments and 9.5% in Goochland Terrane. USGS gives the first a radon index of 8, in the low band (5 to 8), and the second 13, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Tertiary Coastal Plain Sediments | Tertiary Coastal Plain sand, silt, clay | Low | 8 | 90.1% |
| Goochland Terrane | Granite, pegmatites, granitic gneiss, schist and gneiss, slate, and phyllite. | High | 13 | 9.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Caroline County beside the ground around it
Virginia as a whole has more high-potential ground than Caroline County: 47.9% of its land, against 9.5% here. Of the 7 counties that border it, 3 have more high-potential ground, Spotsylvania County the most at 88.1%.
The map rates the ground, not the air in any home.
Local help
Caroline County, Local resources
Radon testing and mitigation in Caroline 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
Caroline County, Questions
Questions about radon in Caroline County
Are radon levels high in Caroline County?
Over the 2008 to 2017 laboratory totals, 32.7% of the radon tests reported to CDC for Caroline County, Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.5 pCi/L. Of 84 Virginia counties with 30 or more tests for the same period, 47 reported a higher share; pooled, the state comes to 30.4%.
Which counties border Caroline County?
Caroline County borders 7 counties: Hanover County, Spotsylvania County, King George County, Essex County, King William County, Stafford County and King and Queen County.
Products
Caroline County, Products
Testing a home in Caroline County
In Caroline County, 32.7% of 199 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 30.4% pooled across Virginia. 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 Caroline 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
MonitorForensics Detectors
FD-65-RADON rechargeable radon detector with a color screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Caroline County, Bordering counties
Counties bordering Caroline County
Calculated by Radon411- Radon levels in King George CountyEPA zone 3
45.5%at or above 4 pCi/L
Median 3.6 pCi/L · 488 tests · 12.8 points above Caroline County
- Radon levels in Spotsylvania CountyEPA zone 1
34.2%at or above 4 pCi/L
Median 2.7 pCi/L · 1,872 tests · 1.5 points above Caroline County
- Radon levels in Stafford CountyEPA zone 1
31.4%at or above 4 pCi/L
Median 2.5 pCi/L · 2,758 tests · 1.3 points below Caroline County
- Radon levels in King and Queen CountyEPA zone 3
28.6%at or above 4 pCi/L
Median 2.4 pCi/L · 7 tests · 4.1 points below Caroline County
- Radon levels in Hanover CountyEPA zone 3
23.0%at or above 4 pCi/L
Median 1.9 pCi/L · 165 tests · 9.7 points below Caroline County
- Radon levels in King William CountyEPA zone 3
14.3%at or above 4 pCi/L
Median 2.4 pCi/L · 7 tests · 18.4 points below Caroline County
- Radon levels in Essex CountyEPA zone 3
7.7%at or above 4 pCi/L
Median 3.2 pCi/L · 13 tests · 25.0 points below Caroline County
Caroline County, Cities and towns
Cities and towns in Caroline County
Caroline County is growing: the Census Bureau puts it at 34,413 residents on July 1, 2025, up 11.3% from 30,922 in 2020. That works out to 65 people per square mile of land. No town dominates: Bowling Green, the largest, has 1,284 residents, 3.7% of the total. Together its 2 incorporated places hold 4.4% of those residents; the other 95.6% live outside any of them. CDC's 199 reported tests for 2008 to 2017 work out to 5.8 per 1,000 residents (2025 estimate), close to Virginia's 6.0.
From Bowling Green to Port Royal, CDC publishes no figure by town: each reads Caroline County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Bowling Green | 1,284 | +10.0% | 3.7% |
| Port Royal | 220 | +11.1% | 0.6% |
2 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).
Caroline County, Homes
Homes in Caroline County
Caroline County is a place of houses on their own lots: 86% of its 12,693 homes are detached single-family houses, against 61% across Virginia. Much of Caroline County is recent building: 39% of its homes have gone up since 2000 and the middle year built is 1992, against 1984 for Virginia. Owners live in 82% of the occupied homes (Virginia: 67%), so for most households a test and a fix are their own to order.
| Homes | Caroline County | Virginia |
|---|---|---|
| Housing units | 12,693 | 3,654,784 |
| Detached houses | 86% | 61% |
| In buildings of 5 or more | 1% | 19% |
| Mobile homes | 6% | 4% |
| Built before 1960 | 14% | 19% |
| Built since 2000 | 39% | 25% |
| Middle year built | 1992 | 1984 |
| Owner-occupied | 82% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.