Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Fairfax city, Virginia
EPA puts Fairfax city in Zone 1, its highest radon zone, and most reported tests there come back low, though 14.3% of 126 (2008 to 2017, laboratory totals) reached 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
14.3%
16.1 pts below VA
- Fairfax city
- 14.3%
- Virginia
- 30.4%
126 tests, 2008 to 2017
Median result
1.4pCi/L
Below action level
- Fairfax city
- 1.4 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
126
52nd of 84 by tests
- Fairfax city
- 126
- 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
76 of 84
Lowest quarter
- Fairfax city
- 14.3%
- Russell
- 67.3%
By share, of 84 with 30+ tests
Read a result for Fairfax city
Starts at Fairfax city's median, 1.4 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.4 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. Fairfax city's median reported result, 2008 to 2017.
The data
Fairfax city, At a glance
Fairfax city at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Fairfax city 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 Fairfax city, 2008 to 2017, laboratory
Under 2 pCi/L: 59%2 to 4 pCi/L: 27%4 pCi/L and above: 14%
Of 126 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 74 | 58.7% |
| 2 to 4 pCi/L | 34 | 27.0% |
| 4 pCi/L and above | 18 | 14.3% |
What these figures count
These are the 126 tests reported to CDC for Fairfax city 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).
Fairfax city, Compared
Fairfax city radon figures, compared
Calculated by Radon411Fairfax city reports fewer high tests than Virginia overall. 14.3% of its 126 tests over the 2008 to 2017 laboratory totals were at or above 4 pCi/L. That is 16.1 points below the 30.4% pooled from 131 Virginia counties.
Ordered from highest share down, it comes 76th of 84 Virginia counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 35.7%; Fairfax city sits 21.4 points below it.
Fairfax County, the one bordering county with a figure for the same period, reported 18.7%. The reported tests do not follow EPA's Zone 1 label for Fairfax city (predicted average above 4 pCi/L): 14.3% of them reached 4 pCi/L, fewer than that label suggests.
Half the tests came in under 1.4 pCi/L and half over it; the single highest reached 14.1 pCi/L. The rest split 58.7% under 2 pCi/L and 27.0% from 2 to 4 (Virginia: 44.7% and 24.9%).
CDC's ten-year totals for Fairfax city went from 100 tests (2005 to 2014) to 126 (2008 to 2017), the share going from 14.0% to 14.3%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Fairfax city, Geology
The ground under Fairfax city
PredictedUSGS's geologic map puts all of Fairfax city's mapped land in one class: high radon potential. All of it lies in the area the map calls Inner Piedmont, to which USGS gives a radon index of 12, 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 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Fairfax city beside the ground around it
Fairfax city has more high-potential ground than Virginia as a whole: 100% of its land against 47.9%. Of the one county that borders it, none has as large a share of high-potential ground; Fairfax County comes nearest at 61.1%.
The map rates the ground, not the air in any home.
Local help
Fairfax city, Local resources
Radon testing and mitigation in Fairfax city
- 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
Fairfax city, Questions
Questions about radon in Fairfax city
Are radon levels high in Fairfax city?
Over the 2008 to 2017 laboratory totals, 14.3% of the radon tests reported to CDC for Fairfax city, Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.4 pCi/L. Of 84 Virginia counties with 30 or more tests for the same period, 75 reported a higher share; pooled, the state comes to 30.4%.
Which counties border Fairfax city?
Fairfax city borders 1 county: Fairfax County.
Products
Fairfax city, Products
Testing a home in Fairfax city
In Fairfax city, 14.3% of 126 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 Fairfax city 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
MonitorPYZYCKYH
RD17 plug-in radon detector with a rechargeable battery and color screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
Short-term kit
PicoCan short-term charcoal canister radon test
- Lab fee included
Method: Charcoal
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Fairfax city is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Fairfax city
Explore
Fairfax city, Bordering counties
Counties bordering Fairfax city
Calculated by Radon411- Radon levels in Fairfax CountyEPA zone 1
18.7%at or above 4 pCi/L
Median 1.5 pCi/L · 8,657 tests · 4.4 points above Fairfax city
Fairfax city, Cities and towns
Cities and towns in Fairfax city
Fairfax city is growing: the Census Bureau puts it at 26,772 residents on July 1, 2025, up 10.7% from 24,174 in 2020. Packed into its land, that is 4,290 people per square mile. Fairfax, its one incorporated place, has 26,772 residents, 100.0% of the total. CDC's 126 reported tests for 2008 to 2017 work out to 4.7 per 1,000 residents (2025 estimate), close to Virginia's 6.0.
Fairfax is the one incorporated place here; CDC publishes no figure by town, so it reads Fairfax city's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Fairfax | 26,772 | +10.7% | 100.0% |
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).
Fairfax city, Homes
Homes in Fairfax city
Fewer than six in ten of Fairfax city's 9,317 homes are detached houses (54%, against 61% across Virginia); the rest are attached, in shared buildings or mobile. The homes are older than Virginia's as a whole: half were built before 1967 (1984 for Virginia), and 32% date from before 1960. 69% of occupied homes are lived in by their owner (Virginia: 67%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Fairfax city | Virginia |
|---|---|---|
| Housing units | 9,317 | 3,654,784 |
| Detached houses | 54% | 61% |
| In buildings of 5 or more | 26% | 19% |
| Mobile homes | 0% | 4% |
| Built before 1960 | 32% | 19% |
| Built since 2000 | 16% | 25% |
| Middle year built | 1967 | 1984 |
| Owner-occupied | 69% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.