Short-term kitKidde
442020 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 3 days
Locations and reports
Radon Levels in King William County, Virginia
EPA puts King William County in Zone 3, its lowest radon zone, and only 7 radon tests from it are on file with CDC (2008 to 2017, laboratory totals). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Highest bordering
36.3%
Caroline County
- Caroline
- 36.3%
- Hanover
- 16.0%
2 of 4 neighbours have 30+ tests, 2006 to 2015
Nearest county
25.7%
Henrico County, 21 miles
- Henrico
- 25.7%
- Virginia
- 30.7%
Share at 4+ pCi/L, 573 tests, 2006 to 2015
Ground above low
None
77.9 pts below Virginia
- King William
- 0.0%
- Virginia
- 77.9%
Share of land USGS rates moderate or high potential
Tests reported
7
Too few for a share
- King William
- 7
- Needed
- 30
2008 to 2017, laboratory
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Read a result for King William County
Starts at EPA's action level
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.0 pCi/L
At or above 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher.
The data
King William County, At a glance
King William County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 96% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for King William County, 2008 to 2017, laboratory
CDC holds 7 reported tests for King William County over the 2008 to 2017 laboratory totals, with a median of 2.4 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). King William County beside the counties around it is how this page reads it.
What these figures count
Only 7 tests were reported to CDC for King William County over 2008 to 2017 (laboratory totals), 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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
King William County, Compared
King William County radon figures, compared
Calculated by Radon411CDC's largest figure for King William County rests on 7 tests over the 2008 to 2017 laboratory totals, 1 of them at or above 4 pCi/L, so each test moves its share by 14.3 points and no rank or comparison is drawn from it. Results reached as high as 5.5 pCi/L, with a middle value of 2.4 pCi/L.
Of the counties bordering it, 2 have a figure over the 2006 to 2015 laboratory totals: Caroline County reported the largest share at or above 4 pCi/L, 36.3%, and Hanover County the smallest, 16.0%. Farther out, Henrico County (21 miles away) at 25.7%, Richmond city (24 miles away) at 28.0% and James City County (31 miles away) at 38.4% have figures too. Pooled across 132 Virginia counties, 30.7% of reported tests reached that level; across every county in the country with a figure, 36.3%.
Statewide for the same period, Russell County reported the highest share (68.5%) and Norfolk city the lowest (5.3%). EPA's 1993 map puts King William County in Zone 3, its lowest label: a predicted county average under 2 pCi/L. USGS geology rates 96% of the county's land low radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
King William County, Geology
The ground under King William County
PredictedUSGS's geologic map puts all of King William County's mapped land in one class: low radon potential. 95.8% of it lies in the area the map calls Tertiary Coastal Plain Sediments, to which USGS gives a radon index of 8, in the low band (5 to 8).
| 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 | 95.8% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
King William County beside the ground around it
Across Virginia 47.9% of the land is rated high; none of King William County's is. Of the 4 counties that border it, 2 have more high-potential ground, Hanover County the most at 52.2%.
The map rates the ground, not the air in any home.
Local help
King William County, Local resources
Radon testing and mitigation in King William 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
King William County, Questions
Questions about radon in King William County
Are radon levels high in King William County?
Over the 2008 to 2017 laboratory totals, 14.3% of the radon tests reported to CDC for King William County, Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.4 pCi/L. Of the counties bordering it, 2 have a figure over the 2006 to 2015 laboratory totals: Caroline County reported the largest share at or above 4 pCi/L, 36.3%, and Hanover County the smallest, 16.0%.
Which counties border King William County?
King William County borders 4 counties: King and Queen County, New Kent County, Hanover County and Caroline County.
Products
King William County, Products
Testing a home in King William County
No CDC figure names King William County; the nearest county with one, Henrico County (21 miles away), reported 25.7% of its tests at or above 4 pCi/L over the 2006 to 2015 laboratory totals, the only reading nearby until a test of this home. 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 King William County.
Test kits and monitors3
See every kit and monitor
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
MonitorSafetySiren
Pro4 plug-in radon detector with a display and alarm
- C-NRPP 2024/25: Not included
- Plug-in
- Alarm
- Screen
First reading: Within 48 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
King William County, Bordering counties
Counties bordering King William County
Calculated by Radon411- Radon levels in New Kent CountyEPA zone 3
41.7%at or above 4 pCi/L
Median 2.8 pCi/L · 12 tests
- Radon levels in Caroline CountyEPA zone 3
36.3%at or above 4 pCi/L
Median 2.6 pCi/L · 135 tests
- Radon levels in King and Queen CountyEPA zone 3
28.6%at or above 4 pCi/L
Median 2.4 pCi/L · 7 tests
- Radon levels in Hanover CountyEPA zone 3
16.0%at or above 4 pCi/L
Median 1.4 pCi/L · 144 tests
King William County, Cities and towns
Cities and towns in King William County
King William County is growing: the Census Bureau puts it at 19,617 residents on July 1, 2025, up 9.5% from 17,916 in 2020. That works out to 72 people per square mile of land. West Point, its one incorporated place, has 3,595 residents, 18.3% of the total. Reported testing is thin here: 7 tests over 2008 to 2017, or 0.4 for every 1,000 residents (2025 estimate), where Virginia as a whole comes to 6.0.
West Point is the one incorporated place here; CDC publishes no figure by town, so it reads King William County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| West Point | 3,595 | +5.0% | 18.3% |
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).
King William County, Homes
Homes in King William County
King William County is a place of houses on their own lots: 93% of its 7,605 homes are detached single-family houses, against 61% across Virginia. Much of King William County is recent building: 41% of its homes have gone up since 2000 and the middle year built is 1995, against 1984 for Virginia. Owners live in 89% of the occupied homes (Virginia: 67%), so for most households a test and a fix are their own to order.
| Homes | King William County | Virginia |
|---|---|---|
| Housing units | 7,605 | 3,654,784 |
| Detached houses | 93% | 61% |
| In buildings of 5 or more | 2% | 19% |
| Mobile homes | 3% | 4% |
| Built before 1960 | 16% | 19% |
| Built since 2000 | 41% | 25% |
| Middle year built | 1995 | 1984 |
| Owner-occupied | 89% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.