Short-term kitFirst Alert
RD1 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 2 to 4 days
Locations and reports
Radon Levels in Clark County, Kansas
EPA puts Clark County in Zone 2, its middle radon zone, and only 9 radon tests from it are on file with CDC (2021). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Highest bordering
42.4%
Ford County
- Ford
- 42.4%
1 of 6 neighbours have 30+ tests, 2019
Nearest county
42.4%
Ford County, 32 miles
- Ford
- 42.4%
- Kansas
- 33.7%
Share at 4+ pCi/L, 165 tests, 2019
Ground above low
100.0%
Level with Kansas
- Clark
- 100.0%
- Kansas
- 100.0%
Share of land USGS rates moderate or high potential
Tests reported
9
Too few for a share
- Clark
- 9
- Needed
- 30
2021
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Read a result for Clark 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
Clark County, At a glance
Clark County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Clark County is a
USGS geologic potential: High across 51% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Clark County, 2021
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2016 | 66.7% |
| 2019 | 0.0% |
| 2021 | 33.3% |
2021: 33.3%. Across these years the share ran from 0.0% to 66.7%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 9 tests were reported to CDC for Clark County over 2021, 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: 2021. Measured data period: 2016 to 2021 (every CDC figure on file).
Clark County, Compared
Clark County radon figures, compared
Calculated by Radon411CDC's largest figure for Clark County rests on 9 tests in 2021, 3 of them at or above 4 pCi/L, so each test moves its share by 11.1 points and no rank or comparison is drawn from it. Results reached as high as 9.7 pCi/L, with a middle value of 2.3 pCi/L.
Ford County, the one bordering county with a figure in 2019, reported 42.4% of its tests at or above 4 pCi/L. Farther out, Seward County (57 miles away) at 52.2%, Pawnee County (73 miles away) at 66.7% and Finney County (75 miles away) at 30.1% have figures too. Pooled across 102 Kansas counties, 33.7% of reported tests reached that level; across every county in the country with a figure, 29.0%.
Statewide for the same period, Jewell County reported the highest share (71.9%) and Reno County the lowest (20.8%). EPA's 1993 map puts Clark County in Zone 2, its middle label: a predicted county average between 2 and 4 pCi/L. USGS geology rates 51% of the county's land high radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Clark County, Geology
The ground under Clark County
PredictedUSGS's geologic map splits Clark County: 50.8% of its land is high radon potential and 49.2% moderate. The map puts 50.8% of Clark County in the area it calls Ogallala Formation and 49.2% in Glaciated Area. USGS gives the first a radon index of 12, in the high band (12 to 17), and the second 9, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Ogallala Formation | Tertiary sandstone, in part covered by windblown eolian sand and loess deposits. | High | 12 | 50.8% |
| Glaciated Area | Glacial till underlain by Pennsylvanian and Permian marine and nonmarine sedimentary shale, sandstone, limestone, coal. | Moderate | 9 | 49.2% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Clark County beside the ground around it
On high-potential ground Clark County is close to Kansas as a whole: 50.8% of its land against 59.9%. Of the 6 counties that border it, 3 have more high-potential ground, Ford County the most at 77.0%.
The map rates the ground, not the air in any home.
Local help
Clark County, Local resources
Radon testing and mitigation in Clark County
- Kansas Radon ProgramKansas Radon Program answers questions about testing, mitigation and the rules in Kansas.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 Kansas178 professionals are listed in Kansas.
What Kansas's program says
- Phone
- (800) 693-5343
What it means
Clark County, Questions
Questions about radon in Clark County
Are radon levels high in Clark County?
In 2021, 33.3% of the radon tests reported to CDC for Clark County, Kansas were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.3 pCi/L. Ford County, the one bordering county with a figure in 2019, reported 42.4% of its tests at or above 4 pCi/L.
Which counties border Clark County?
Clark County borders 6 counties: Ford County, KS, Comanche County, KS, Meade County, KS, Harper County, OK, Kiowa County, KS and Beaver County, OK.
Products
Clark County, Products
Testing a home in Clark County
No CDC figure names Clark County; the nearest county with one, Ford County (32 miles away), reported 42.4% of its tests at or above 4 pCi/L in 2019, the only reading nearby until a test of this home. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Clark County; a long-term test tells the year-round average.
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
View Plus radon and air quality monitor
- C-NRPP 2024/25: Approved
- Battery
- Wi-Fi, Bluetooth
- Screen, app
Method: Alpha spectrometry
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Clark County, Bordering counties
Counties bordering Clark County
Calculated by Radon411- Radon levels in Ford County, KSEPA zone 1
42.4%at or above 4 pCi/L
Median 3.3 pCi/L · 165 tests
- Radon levels in Meade County, KSEPA zone 1
33.3%at or above 4 pCi/L
Median 2.7 pCi/L · 6 tests
- Radon levels in Kiowa County, KSEPA zone 1
0.0%at or above 4 pCi/L
Median 3.8 pCi/L · 1 test
- Radon levels in Comanche County, KSEPA zone 2
No CDC figure for 2019; its page reads it against its own neighbours.
- Radon levels in Harper County, OKEPA zone 3
No CDC figure for 2019; its page reads it against its own neighbours.
- Radon levels in Beaver County, OKEPA zone 2
No CDC figure for 2019; its page reads it against its own neighbours.
Clark County, Cities and towns
Cities and towns in Clark County
About 1,900 people live in Clark County by the Census Bureau's estimate for July 1, 2025, 76 fewer than in 2020 (−3.8%). Spread over its land, that is 1.9 people to the square mile. Its largest town, Ashland, has 744 residents, 39.2% of the total. Together its 3 incorporated places hold 79.3% of those residents; the other 20.7% live outside any of them. Reported testing is thin here: 9 tests over 2021, or 4.7 for every 1,000 residents (2025 estimate), where Kansas as a whole comes to 23.5.
From Ashland to Englewood, CDC publishes no figure by town: each reads Clark County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Ashland | 744 | −4.4% | 39.2% |
| Minneola | 711 | −3.4% | 37.4% |
| Englewood | 52 | −3.7% | 2.7% |
3 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).
Clark County, Homes
Homes in Clark County
Clark County is a place of houses on their own lots: 91% of its 1,066 homes are detached single-family houses, against 72% across Kansas. The homes are older than Kansas' as a whole: half were built before 1949 (1975 for Kansas), and 64% date from before 1960. Owners live in 76% of the occupied homes (Kansas: 67%), so for most households a test and a fix are their own to order.
| Homes | Clark County | Kansas |
|---|---|---|
| Housing units | 1,066 | 1,285,221 |
| Detached houses | 91% | 72% |
| In buildings of 5 or more | 2% | 13% |
| Mobile homes | 4% | 4% |
| Built before 1960 | 64% | 33% |
| Built since 2000 | 7% | 20% |
| Middle year built | 1949 | 1975 |
| Owner-occupied | 76% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.