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 Louisa County, Virginia
EPA puts Louisa County in Zone 1, its highest radon zone, and 38.1% of its 289 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
38.1%
7.7 pts above VA
- Louisa
- 38.1%
- Virginia
- 30.4%
289 tests, 2008 to 2017
Median result
2.8pCi/L
Below action level
- Louisa
- 2.8 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
289
38th of 84 by tests
- Louisa
- 289
- Fairfax
- 8,657
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in Virginia
34 of 84
Middle half
- Louisa
- 38.1%
- Russell
- 67.3%
By share, of 84 with 30+ tests
Read a result for Louisa County
Starts at Louisa County's median, 2.8 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.8 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. Louisa County's median reported result, 2008 to 2017.
The data
Louisa County, At a glance
Louisa County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Louisa County in
USGS geologic potential: High across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Louisa County, 2008 to 2017, laboratory
Under 2 pCi/L: 38%2 to 4 pCi/L: 24%4 pCi/L and above: 38%
Of 289 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 110 | 38.1% |
| 2 to 4 pCi/L | 69 | 23.9% |
| 4 pCi/L and above | 110 | 38.1% |
What these figures count
These are the 289 tests reported to CDC for Louisa 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).
Louisa County, Compared
Louisa County radon figures, compared
Calculated by Radon411In Louisa County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (110 of 289) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 2.4 points higher. Across 131 Virginia counties pooled together, 30.4% of tests reached that level, so Louisa County runs 7.7 points above its state.
Of 6 neighbours with a figure, none reported a larger share at or above 4 pCi/L; the spread is 23.0% (Hanover County) to 36.1% (Orange County). By share, Louisa County is 34th of 84 Virginia counties with 30 or more tests for the same period.
Half the tests came in under 2.8 pCi/L and half over it; the single highest reached 25.0 pCi/L. Below the action level, 110 tests (38.1%) came in under 2 pCi/L, against 44.7% statewide, and 69 tests (23.9%) fell between 2 and 4, against 24.9% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 38.1% share point the same way here. USGS geology rates 100% of the county's land high radon potential. CDC also counts 38 tests taken after mitigation in Louisa County for the same period: tests in homes where a fix was already in.
CDC's ten-year totals for Louisa County went from 177 tests (2005 to 2014) to 289 (2008 to 2017), the share going from 37.9% to 38.1%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Louisa County, Geology
The ground under Louisa County
PredictedUSGS's geologic map puts all of Louisa County's mapped land in one class: high radon potential. The map puts 72.9% of Louisa County in the area it calls Inner Piedmont and 27.1% in Goochland Terrane. USGS gives the first a radon index of 12 and the second 13, both in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Inner Piedmont | Granite, pegmatites, granitic gneiss, schist and gneiss, slate, and phyllite. | High | 12 | 72.9% |
| Goochland Terrane | Granite, pegmatites, granitic gneiss, schist and gneiss, slate, and phyllite. | High | 13 | 27.1% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Louisa County beside the ground around it
Louisa County has more high-potential ground than Virginia as a whole: 100% of its land against 47.9%. Of the 6 counties that border it, none has as large a share of high-potential ground; Fluvanna County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Louisa County, Local resources
Radon testing and mitigation in Louisa 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
Louisa County, Questions
Questions about radon in Louisa County
Are radon levels high in Louisa County?
Over the 2008 to 2017 laboratory totals, 38.1% of the radon tests reported to CDC for Louisa County, Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.8 pCi/L. Of 84 Virginia counties with 30 or more tests for the same period, 33 reported a higher share; pooled, the state comes to 30.4%.
Which counties border Louisa County?
Louisa County borders 6 counties: Goochland County, Fluvanna County, Spotsylvania County, Orange County, Hanover County and Albemarle County.
Products
Louisa County, Products
Testing a home in Louisa County
In Louisa County, 38.1% of 289 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 30.4% pooled across Virginia. In Zone 1 the year-round level in Louisa 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
Monitor
RadonScan-Plus USB-powered radon monitor with Wi-Fi
- C-NRPP 2024/25: Not included
- Plug-in
- Wi-Fi
- Alarm
- Screen, app
First reading: Within 5 minutes
Short-term kit
RA100 short-term liquid scintillation radon test kit
- Lab fee extra
Method: Liquid scintillation
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Louisa County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Louisa County
Explore
Louisa County, Bordering counties
Counties bordering Louisa County
Calculated by Radon411- Radon levels in Orange CountyEPA zone 1
36.1%at or above 4 pCi/L
Median 2.8 pCi/L · 462 tests · 2.0 points below Louisa County
- Radon levels in Spotsylvania CountyEPA zone 1
34.2%at or above 4 pCi/L
Median 2.7 pCi/L · 1,872 tests · 3.9 points below Louisa County
- Radon levels in Goochland CountyEPA zone 1
30.7%at or above 4 pCi/L
Median 2.4 pCi/L · 114 tests · 7.4 points below Louisa County
- Radon levels in Fluvanna CountyEPA zone 1
28.1%at or above 4 pCi/L
Median 2.5 pCi/L · 388 tests · 10.0 points below Louisa County
- Radon levels in Albemarle CountyEPA zone 2
24.7%at or above 4 pCi/L
Median 2.1 pCi/L · 2,179 tests · 13.4 points below Louisa County
- Radon levels in Hanover CountyEPA zone 3
23.0%at or above 4 pCi/L
Median 1.9 pCi/L · 165 tests · 15.1 points below Louisa County
Louisa County, Cities and towns
Cities and towns in Louisa County
Louisa County is growing: the Census Bureau puts it at 42,924 residents on July 1, 2025, up 13.6% from 37,785 in 2020. That works out to 87 people per square mile of land. No town dominates: Louisa, the largest, has 2,244 residents, 5.2% of the total. Together its 2 incorporated places hold 6.5% of those residents; the other 93.5% live outside any of them. CDC's 289 reported tests for 2008 to 2017 work out to 6.7 per 1,000 residents (2025 estimate), close to Virginia's 6.0.
From Louisa to Mineral, CDC publishes no figure by town: each reads Louisa County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Louisa | 2,244 | +12.6% | 5.2% |
| Mineral | 532 | +13.0% | 1.2% |
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).
Louisa County, Homes
Homes in Louisa County
Louisa County is a place of houses on their own lots: 84% of its 18,047 homes are detached single-family houses, against 61% across Virginia. Much of Louisa County is recent building: 36% of its homes have gone up since 2000 and the middle year built is 1994, against 1984 for Virginia. Owners live in 81% of the occupied homes (Virginia: 67%), so for most households a test and a fix are their own to order.
| Homes | Louisa County | Virginia |
|---|---|---|
| Housing units | 18,047 | 3,654,784 |
| Detached houses | 84% | 61% |
| In buildings of 5 or more | 3% | 19% |
| Mobile homes | 10% | 4% |
| Built before 1960 | 12% | 19% |
| Built since 2000 | 36% | 25% |
| Middle year built | 1994 | 1984 |
| Owner-occupied | 81% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.