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
Locations and reports
Radon Levels in Gray County, Kansas
EPA puts Gray County in Zone 1, its highest radon zone, and only 14 radon tests from it are on file with CDC (2022). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
41.2%
9.4 pts above KS
- Gray
- 41.2%
- Kansas
- 31.8%
51 tests, 2021
Median result
3.6pCi/L
Below action level
- Gray
- 3.6 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2021
Tests reported
51
46th of 62 by tests
- Gray
- 51
- Johnson
- 25,860
Reported to CDC before any fix, 2021
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in Kansas
25 of 62
Middle half
- Gray
- 41.2%
- Norton
- 93.8%
By share, of 62 with 30+ tests
Read a result for Gray County
Starts at Gray County's median, 3.6 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.6 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. Gray County's median reported result, 2021.
The data
Gray County, At a glance
Gray County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Gray County in
USGS geologic potential: High across 72% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Gray County, 2022
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2016 | 55.6% |
| 2017 | 60.0% |
| 2018 | 15.8% |
| 2019 | 44.4% |
| 2020 | 26.7% |
| 2021 | 41.2% |
| 2022 | 35.7% |
2022: 35.7%. Across these years the share ran from 15.8% to 60.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 14 tests were reported to CDC for Gray County over 2022, 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: 2022. Measured data period: 2016 to 2022 (every CDC figure on file).
Gray County, Compared
Gray County radon figures, compared
Calculated by Radon411In Gray County, about 4 in 10 reported tests in 2021 (21 of 51) were at or above EPA's action level. Against the national pool of 24.4%, the gap is 16.8 points higher. Across 96 Kansas counties pooled together, 31.8% of tests reached that level, so Gray County runs 9.4 points above its state.
The newest figure, in 2022, counts only 14 tests (35.7% at or above 4 pCi/L), too few to compare, so this reading uses the 51-test figure.
Of 2 neighbours with a figure, 1 reported a larger share at or above 4 pCi/L and 1 a smaller one; the spread is 33.3% (Finney County) to 57.9% (Ford County). By share, Gray County is 25th of 62 Kansas counties with 30 or more tests for the same period.
Half the tests came in under 3.6 pCi/L and half over it; the single highest reached 21.0 pCi/L. Below the action level, 6 tests (11.8%) came in under 2 pCi/L, against 45.3% statewide, and 24 tests (47.1%) fell between 2 and 4, against 22.9% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 41.2% share point the same way here. USGS geology rates 72% of the county's land high radon potential. CDC also counts 9 tests taken after mitigation in Gray County for the same period: tests in homes where a fix was already in.
The busiest year on file was 2021, with 51 tests reported; the quietest, 2017, had 5.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Gray County, Geology
The ground under Gray County
PredictedUSGS's geologic map splits Gray County: 71.7% of its land is high radon potential and 28.3% moderate. The map puts 71.7% of Gray County in the area it calls Ogallala Formation and 28.3% in Arkansas River Lowlands. USGS gives the first a radon index of 12, in the high band (12 to 17), and the second 10, 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 | 71.7% |
| Arkansas River Lowlands | Dune sands and alluvium. | Moderate | 10 | 28.3% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Gray County beside the ground around it
Gray County has more high-potential ground than Kansas as a whole: 71.7% of its land against 59.9%. Of the 5 counties that border it, 4 have more high-potential ground, Hodgeman County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Gray County, Local resources
Radon testing and mitigation in Gray 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
Gray County, Questions
Questions about radon in Gray County
Are radon levels high in Gray County?
In 2022, 35.7% of the radon tests reported to CDC for Gray County, Kansas were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.0 pCi/L. Of 62 Kansas counties with 30 or more tests for the same period, 24 reported a higher share; pooled, the state comes to 31.8%.
Which counties border Gray County?
Gray County borders 5 counties: Finney County, Haskell County, Ford County, Hodgeman County and Meade County.
Products
Gray County, Products
Testing a home in Gray County
In Gray County, 41.2% of 51 tests reported to CDC in 2021 reached 4 pCi/L, against 31.8% pooled across Kansas. In Zone 1 the year-round level in Gray County 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
MonitorAranet
Radon Plus battery digital radon monitor with an e-ink screen
- C-NRPP 2024/25: Approved
- Battery
- Bluetooth
- Alarm
- Screen, app
Method: Ion chamber
First reading: Within 10 minutes
Short-term kit
RA100 short-term liquid scintillation radon test kit
- Lab fee extra
Method: Liquid scintillation
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Gray County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Gray County
Explore
Gray County, Bordering counties
Counties bordering Gray County
Calculated by Radon411- Radon levels in Meade CountyEPA zone 1
62.5%at or above 4 pCi/L
Median 6.4 pCi/L · 24 tests · 21.3 points above Gray County
- Radon levels in Haskell CountyEPA zone 1
60.0%at or above 4 pCi/L
Median 4.3 pCi/L · 15 tests · 18.8 points above Gray County
- Radon levels in Ford CountyEPA zone 1
57.9%at or above 4 pCi/L
Median 4.8 pCi/L · 228 tests · 16.7 points above Gray County
- Radon levels in Hodgeman CountyEPA zone 1
50.0%at or above 4 pCi/L
Median 4.6 pCi/L · 12 tests · 8.8 points above Gray County
- Radon levels in Finney CountyEPA zone 1
33.3%at or above 4 pCi/L
Median 3.1 pCi/L · 243 tests · 7.9 points below Gray County
Gray County, Cities and towns
Cities and towns in Gray County
Gray County's population has barely moved since 2020: 5,652 residents on July 1, 2025 against 5,644 then, by the Census Bureau's estimates. Spread over its land, that is 6.5 people to the square mile. Its largest town, Cimarron, has 1,935 residents, 34.2% of the total. Together its 5 incorporated places hold 63.2% of those residents; the other 36.8% live outside any of them. Reported testing is thin here: 51 tests over 2021, or 9.0 for every 1,000 residents (2025 estimate), where Kansas as a whole comes to 23.5.
From Cimarron to Ensign, CDC publishes no figure by town: each reads Gray County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Cimarron | 1,935 | −1.8% | 34.2% |
| Montezuma | 978 | +0.5% | 17.3% |
| Copeland | 248 | −2.4% | 4.4% |
| Ingalls | 248 | −2.4% | 4.4% |
| Ensign | 163 | −2.4% | 2.9% |
5 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).
Gray County, Homes
Homes in Gray County
Gray County is a place of houses on their own lots: 82% of its 2,339 homes are detached single-family houses, against 72% across Kansas. Half of its homes were built before 1975, close to Kansas' 1975: 33% date from before 1960 and 13% from 2000 or later. Owners live in 80% of the occupied homes (Kansas: 67%), so for most households a test and a fix are their own to order.
| Homes | Gray County | Kansas |
|---|---|---|
| Housing units | 2,339 | 1,285,221 |
| Detached houses | 82% | 72% |
| In buildings of 5 or more | 4% | 13% |
| Mobile homes | 11% | 4% |
| Built before 1960 | 33% | 33% |
| Built since 2000 | 13% | 20% |
| Middle year built | 1975 | 1975 |
| Owner-occupied | 80% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.