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 Washington County, Arkansas
EPA puts Washington County in Zone 3, its lowest radon zone, and most reported tests there come back low, though 13.0% of 54 (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
13.0%
10.2 pts below AR
- Washington
- 13.0%
- Arkansas
- 23.2%
54 tests, 2008 to 2017
Median result
2.2pCi/L
Below action level
- Washington
- 2.2 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
54
3rd of 5 by tests
- Washington
- 54
- Benton
- 147
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 Arkansas
4 of 5
Middle half
- Washington
- 13.0%
- Garland
- 45.5%
By share, of 5 with 30+ tests
Read a result for Washington County
Starts at Washington County's median, 2.2 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.2 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. Washington County's median reported result, 2008 to 2017.
The data
Washington County, At a glance
Washington County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Moderate across 65% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Washington County, 2008 to 2017, laboratory
Under 2 pCi/L: 48%2 to 4 pCi/L: 39%4 pCi/L and above: 13%
Of 54 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 26 | 48.1% |
| 2 to 4 pCi/L | 21 | 38.9% |
| 4 pCi/L and above | 7 | 13.0% |
What these figures count
These are the 54 tests reported to CDC for Washington 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).
Washington County, Compared
Washington County radon figures, compared
Calculated by Radon411Washington County reports fewer high tests than Arkansas overall. 13.0% of its 54 tests over the 2008 to 2017 laboratory totals were at or above 4 pCi/L. That is 10.2 points below the 23.2% pooled from 58 Arkansas counties.
Ordered from highest share down, it comes 4th of 5 Arkansas counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 35.7%; Washington County sits 22.7 points below it.
Benton County, the one bordering county with a figure for the same period, reported 34.0%. Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 13.0% share point the same way here.
Half the tests came in under 2.2 pCi/L and half over it; the single highest reached 5.6 pCi/L. The rest split 48.1% under 2 pCi/L and 38.9% from 2 to 4 (Arkansas: 55.5% and 21.3%).
CDC's ten-year totals for Washington County went from 52 tests (2005 to 2014) to 54 (2008 to 2017), the share going from 13.5% to 13.0%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Washington County, Geology
The ground under Washington County
PredictedUSGS's geologic map splits Washington County: 65.2% of its land is moderate radon potential and 34.8% low. The map puts 63.6% of Washington County in the area it calls Springfield Plateau and 34.8% in Boston Mountains, with one smaller area beside them. USGS gives the first a radon index of 9, in the moderate band (9 to 11), and the second 8, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Springfield Plateau | Mississippian limestone, shale, and sandstone. | Moderate | 9 | 63.6% |
| Boston Mountains | Mississippian and Pennsylvanian sandstones and shales. | Low | 8 | 34.8% |
| Salem Plateau | Ordovician dolomite. | Moderate | 9 | 1.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Washington County beside the ground around it
Washington County has more moderate-potential ground than Arkansas as a whole: 65.2% of its land against 21.3%. Of the 4 counties that border it, 2 have more moderate-potential ground, Benton County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Washington County, Local resources
Radon testing and mitigation in Washington County
- Arkansas's radon programArkansas Department of HealthArkansas's radon program answers questions about testing, mitigation and the rules in Arkansas.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
- See the Arkansas directoryNo professionals are listed in Arkansas yet. The state program can point you to registered testers and mitigators.
What Arkansas's program says
- Phone
- 501-661-2621
- ADH.EPI.Radon@arkansas.gov
What it means
Washington County, Questions
Questions about radon in Washington County
Are radon levels high in Washington County?
Over the 2008 to 2017 laboratory totals, 13.0% of the radon tests reported to CDC for Washington County, Arkansas were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.2 pCi/L. Of 5 Arkansas counties with 30 or more tests for the same period, 3 reported a higher share; pooled, the state comes to 23.2%.
Which counties border Washington County?
Washington County borders 4 counties: Benton County, AR, Adair County, OK, Crawford County, AR and Madison County, AR.
Products
Washington County, Products
Testing a home in Washington County
In Washington County, 13.0% of 54 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 23.2% pooled across Arkansas. 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 Washington 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
Explore
Washington County, Bordering counties
Counties bordering Washington County
Calculated by Radon411- Radon levels in Adair County, OKEPA zone 2
50.0%at or above 4 pCi/L
Median 3.8 pCi/L · 2 tests · 37.0 points above Washington County
- Radon levels in Benton County, AREPA zone 2
34.0%at or above 4 pCi/L
Median 2.2 pCi/L · 147 tests · 21.0 points above Washington County
- Radon levels in Madison County, AREPA zone 3
16.7%at or above 4 pCi/L
Median 1.2 pCi/L · 6 tests · 3.7 points above Washington County
- Radon levels in Crawford County, AREPA zone 3
11.1%at or above 4 pCi/L
Median 0.7 pCi/L · 9 tests · 1.9 points below Washington County
Washington County, Cities and towns
Cities and towns in Washington County
Washington County is growing: the Census Bureau puts it at 271,213 residents on July 1, 2025, up 9.9% from 246,756 in 2020. That works out to 288 people per square mile of land. Its largest town, Fayetteville, has 106,623 residents, 39.3% of the total. CDC's 54 reported tests for 2008 to 2017 work out to 0.2 per 1,000 residents (2025 estimate), close to Arkansas' 0.2.
From Fayetteville to Winslow, CDC publishes no figure by town: each reads Washington County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Fayetteville | 106,623 | +12.5% | 39.3% |
| Springdaleextends beyond Washington County | 90,685 | +3.9% | Counted whole |
| Farmington | 10,658 | +39.8% | 3.9% |
| Prairie Grove | 8,998 | +26.2% | 3.3% |
| Tontitown | 8,046 | +71.7% | 3.0% |
| Elkins | 4,184 | +15.1% | 1.5% |
| Johnson | 3,684 | +2.2% | 1.4% |
| Elm Springsextends beyond Washington County | 2,852 | +18.8% | Counted whole |
| Goshen | 2,405 | +13.9% | 0.9% |
| West Fork | 2,373 | +1.5% | 0.9% |
| Lincoln | 2,370 | +3.9% | 0.9% |
| Greenland | 1,544 | +0.3% | 0.6% |
- Winslow
13 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. “(part)” marks a place that extends into another county. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025). A place that extends beyond Washington County is counted whole, so it has no share.
Washington County, Homes
Homes in Washington County
Of Washington County's 103,174 homes, 63% are detached houses, against 70% across Arkansas; 20% are in buildings of five or more homes. Half of its homes were built before 1994, close to Arkansas' 1987: 8% date from before 1960 and 39% from 2000 or later. 56% of occupied homes are lived in by their owner (Arkansas: 66%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Washington County | Arkansas |
|---|---|---|
| Housing units | 103,174 | 1,382,664 |
| Detached houses | 63% | 70% |
| In buildings of 5 or more | 20% | 10% |
| Mobile homes | 5% | 11% |
| Built before 1960 | 8% | 14% |
| Built since 2000 | 39% | 28% |
| Middle year built | 1994 | 1987 |
| Owner-occupied | 56% | 66% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.