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 Northumberland County, Virginia
EPA puts Northumberland County in Zone 3, its lowest radon zone, and only 15 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
14.3%
Westmoreland County
- Westmoreland
- 14.3%
1 of 3 neighbours have 30+ tests, 2006 to 2015
Nearest county
14.3%
Westmoreland County, 26 miles
- Westmoreland
- 14.3%
- Virginia
- 30.7%
Share at 4+ pCi/L, 35 tests, 2006 to 2015
Ground above low
None
77.9 pts below Virginia
- Northumberland
- 0.0%
- Virginia
- 77.9%
Share of land USGS rates moderate or high potential
Tests reported
16
Too few for a share
- Northumberland
- 16
- Needed
- 30
2005 to 2014, 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 Northumberland 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
Northumberland County, At a glance
Northumberland County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 85% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Northumberland County, 2008 to 2017, laboratory
CDC holds 15 reported tests for Northumberland County over the 2008 to 2017 laboratory totals, with a median of 1.0 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Northumberland County beside the counties around it is how this page reads it.
What these figures count
Only 15 tests were reported to CDC for Northumberland 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).
Northumberland County, Compared
Northumberland County radon figures, compared
Calculated by Radon411CDC's largest figure for Northumberland County rests on 16 tests over the 2005 to 2014 laboratory totals, 4 of them at or above 4 pCi/L, so each test moves its share by 6.3 points and no rank or comparison is drawn from it. Results reached as high as 31.2 pCi/L, with a middle value of 1.2 pCi/L.
Westmoreland County, the one bordering county with a figure over the 2006 to 2015 laboratory totals, reported 14.3% of its tests at or above 4 pCi/L. Farther out, James City County (43 miles away) at 38.4%, King George County (48 miles away) at 47.6% and Caroline County (52 miles away) at 36.3% 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 Northumberland County in Zone 3, its lowest label: a predicted county average under 2 pCi/L. USGS geology rates 85% of the county's land low radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Northumberland County, Geology
The ground under Northumberland County
PredictedUSGS's geologic map puts all of Northumberland County's mapped land in one class: low radon potential. 85.3% 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 | 85.3% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Northumberland County beside the ground around it
Across Virginia 47.9% of the land is rated high; none of Northumberland County's is. None of the 3 counties that border it has any moderate-potential ground either.
The map rates the ground, not the air in any home.
Local help
Northumberland County, Local resources
Radon testing and mitigation in Northumberland 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
Northumberland County, Questions
Questions about radon in Northumberland County
Are radon levels high in Northumberland County?
Over the 2008 to 2017 laboratory totals, 13.3% of the radon tests reported to CDC for Northumberland County, Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.0 pCi/L. Westmoreland County, the one bordering county with a figure over the 2006 to 2015 laboratory totals, reported 14.3% of its tests at or above 4 pCi/L.
Which counties border Northumberland County?
Northumberland County borders 3 counties: Lancaster County, Richmond County and Westmoreland County.
Products
Northumberland County, Products
Testing a home in Northumberland County
No CDC figure names Northumberland County; the nearest county with one, Westmoreland County (26 miles away), reported 14.3% 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 Northumberland 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
Monitor
RadonScan USB-powered radon monitor with a color screen
- C-NRPP 2024/25: Not included
- Plug-in
- Alarm
- Screen
First reading: Within 5 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Best radon monitors for Northumberland County homes, compared
Explore
Northumberland County, Bordering counties
Counties bordering Northumberland County
Calculated by Radon411- Radon levels in Richmond CountyEPA zone 3
26.9%at or above 4 pCi/L
Median 1.8 pCi/L · 26 tests
- Radon levels in Lancaster CountyEPA zone 3
25.0%at or above 4 pCi/L
Median 2.5 pCi/L · 12 tests
- Radon levels in Westmoreland CountyEPA zone 3
14.3%at or above 4 pCi/L
Median 1.6 pCi/L · 35 tests
Northumberland County, Cities and towns
Cities and towns in Northumberland County
Northumberland County is growing: the Census Bureau puts it at 12,557 residents on July 1, 2025, up 6.1% from 11,838 in 2020. That works out to 66 people per square mile of land. Kilmarnock, the largest place on its list (1,457 residents in all), extends beyond Northumberland County, so no share of the total is worked out for it. Reported testing is thin here: 16 tests over 2005 to 2014, or 1.3 for every 1,000 residents (2025 estimate), where Virginia as a whole comes to 4.4.
Kilmarnock is the one incorporated place here; CDC publishes no figure by town, so it reads Northumberland County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Kilmarnockextends beyond Northumberland County | 1,457 | +1.0% | Counted whole |
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). A place that extends beyond Northumberland County is counted whole, so it has no share.
Northumberland County, Homes
Homes in Northumberland County
Northumberland County is a place of houses on their own lots: 87% of its 9,009 homes are detached single-family houses, against 61% across Virginia. Half of its homes were built before 1989, close to Virginia's 1984: 19% date from before 1960 and 31% from 2000 or later. 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 | Northumberland County | Virginia |
|---|---|---|
| Housing units | 9,009 | 3,654,784 |
| Detached houses | 87% | 61% |
| In buildings of 5 or more | 1% | 19% |
| Mobile homes | 8% | 4% |
| Built before 1960 | 19% | 19% |
| Built since 2000 | 31% | 25% |
| Middle year built | 1989 | 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.