Short-term kitempowerDX
Standard Radon Test short-term mail-in radon test kit
- Lab fee included
Method: Passive sampler
In home: 48 to 96 hours
Locations and reports
Radon Levels in Ray County, Missouri
EPA puts Ray County in Zone 2, its middle radon zone, and only 7 radon tests from it are on file with CDC (2023). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
38.9%
8.3 pts above MO
- Ray
- 38.9%
- Missouri
- 30.6%
108 tests, 2008 to 2017
Median result
2.5pCi/L
Below action level
- Ray
- 2.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
108
36th of 72 by tests
- Ray
- 108
- St. Louis
- 17,747
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Rank in Missouri
18 of 72
Top quarter
- Ray
- 38.9%
- Atchison
- 69.9%
By share, of 72 with 30+ tests
Read a result for Ray County
Starts at Ray County's median, 2.5 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.5 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. Ray County's median reported result, 2008 to 2017.
The data
Ray County, At a glance
Ray County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Ray County is a
USGS geologic potential: Moderate across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Ray County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 50.0% |
| 2015 | 28.6% |
| 2016 | 45.5% |
| 2017 | 75.0% |
| 2018 | 16.7% |
| 2019 | 0.0% |
| 2020 | 0.0% |
| 2021 | 0.0% |
| 2022 | 66.7% |
| 2023 | 28.6% |
2023: 28.6%. Across these years the share ran from 0.0% to 75.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 7 tests were reported to CDC for Ray County over 2023, 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: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
Ray County, Compared
Ray County radon figures, compared
Calculated by Radon411In Ray County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (42 of 108) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 3.2 points higher. Across 115 Missouri counties pooled together, 30.6% of tests reached that level, so Ray County runs 8.3 points above its state.
The newest figure, in 2023, counts only 7 tests (28.6% at or above 4 pCi/L), too few to compare, so this reading uses the 108-test figure.
Of 4 neighbours with a figure, 3 reported a larger share at or above 4 pCi/L and 1 a smaller one; the spread is 38.1% (Clinton County) to 46.7% (Lafayette County). By share, Ray County is 18th of 72 Missouri counties with 30 or more tests for the same period.
Half the tests came in under 2.5 pCi/L and half over it; the single highest reached 61.4 pCi/L. Below the action level, 40 tests (37.0%) came in under 2 pCi/L, against 41.2% statewide, and 26 tests (24.1%) fell between 2 and 4, against 28.1% statewide.
Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 38.9% share point the same way here. USGS geology rates 100% of the county's land moderate radon potential.
The busiest year on file was 2016, with 11 tests reported; the quietest, 2021, had 1.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Ray County, Geology
The ground under Ray County
PredictedUSGS's geologic map puts all of Ray County's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Dissected Till Plains, to which USGS gives a radon index of 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Dissected Till Plains | Till-covered Pennsylvanian sandstone, shale, and limestone. | Moderate | 11 | 99.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Ray County beside the ground around it
Across Missouri 8.2% of the land is rated high; none of Ray County's is. Of the 6 counties that border it, 3 have more high-potential ground, Clay County the most at 72.6%.
The map rates the ground, not the air in any home.
Local help
Ray County, Local resources
Radon testing and mitigation in Ray County
- Missouri Radon ProgramMissouri Radon Program, run by Missouri Department of Health and Senior Services, offers free or discounted test kits, and answers questions about testing and mitigation in Missouri.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Free radon test kits are available for Missouri residents (limit one per household).
- Compare kits
- Professionals in Missouri27 professionals are listed in Missouri.
What Missouri's program says
- Phone
- 573-751-6102
- radon@health.mo.gov
What it means
Ray County, Questions
Questions about radon in Ray County
Are radon levels high in Ray County?
In 2023, 28.6% of the radon tests reported to CDC for Ray County, Missouri were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.0 pCi/L. Of 72 Missouri counties with 30 or more tests for the same period, 17 reported a higher share; pooled, the state comes to 30.6%.
Which counties border Ray County?
Ray County borders 6 counties: Clay County, Lafayette County, Caldwell County, Carroll County, Clinton County and Jackson County.
Products
Ray County, Products
Testing a home in Ray County
In Ray County, 38.9% of 108 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 30.6% pooled across Missouri. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Ray County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
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
MonitorKidde
Radon Detector (RAB) battery digital radon detector with an alarm
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 12 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Ray County, Bordering counties
Counties bordering Ray County
Calculated by Radon411- Radon levels in Lafayette CountyEPA zone 2
46.7%at or above 4 pCi/L
Median 3.5 pCi/L · 184 tests · 7.8 points above Ray County
- Radon levels in Jackson CountyEPA zone 1
41.3%at or above 4 pCi/L
Median 3.1 pCi/L · 6,618 tests · 2.4 points above Ray County
- Radon levels in Clay CountyEPA zone 1
39.2%at or above 4 pCi/L
Median 3.1 pCi/L · 3,438 tests · 0.3 points above Ray County
- Radon levels in Clinton CountyEPA zone 1
38.1%at or above 4 pCi/L
Median 2.8 pCi/L · 105 tests · 0.8 points below Ray County
- Radon levels in Carroll CountyEPA zone 2
33.3%at or above 4 pCi/L
Median 2.7 pCi/L · 18 tests · 5.6 points below Ray County
- Radon levels in Caldwell CountyEPA zone 2
6.3%at or above 4 pCi/L
Median 1.5 pCi/L · 16 tests · 32.6 points below Ray County
Ray County, Cities and towns
Cities and towns in Ray County
The Census Bureau estimates 23,398 residents in Ray County for July 1, 2025, 262 more than in 2020 (+1.1%). That works out to 41 people per square mile of land. Excelsior Springs, the largest place on its list (10,819 residents in all), extends beyond Ray County, so no share of the total is worked out for it. Reported testing is thin here: 108 tests over 2008 to 2017, or 4.6 for every 1,000 residents (2025 estimate), where Missouri as a whole comes to 9.3.
From Excelsior Springs to Elmira, CDC publishes no figure by town: each reads Ray County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Excelsior Springsextends beyond Ray County | 10,819 | +2.3% | Counted whole |
| Richmond | 5,968 | −0.6% | 25.5% |
| Lawsonextends beyond Ray County | 2,541 | +0.6% | Counted whole |
| Wood Heights | 745 | Level | 3.2% |
| Orrick | 740 | −0.9% | 3.2% |
| Hardin | 560 | −1.4% | 2.4% |
| Crystal Lakes | 395 | +0.8% | 1.7% |
| Henrietta | 273 | −0.7% | 1.2% |
| Excelsior Estatesextends beyond Ray County | 233 | +6.4% | Counted whole |
| Homestead | 190 | Level | 0.8% |
| Camden | 183 | +1.1% | 0.8% |
| Fleming | 115 | +2.7% | 0.5% |
- Elmira
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 Ray County is counted whole, so it has no share.
Ray County, Homes
Homes in Ray County
Ray County is a place of houses on their own lots: 85% of its 9,901 homes are detached single-family houses, against 70% across Missouri. Half of its homes were built before 1974, close to Missouri's 1978: 30% date from before 1960 and 15% from 2000 or later. Owners live in 77% of the occupied homes (Missouri: 68%), so for most households a test and a fix are their own to order.
| Homes | Ray County | Missouri |
|---|---|---|
| Housing units | 9,901 | 2,809,501 |
| Detached houses | 85% | 70% |
| In buildings of 5 or more | 2% | 13% |
| Mobile homes | 4% | 5% |
| Built before 1960 | 30% | 28% |
| Built since 2000 | 15% | 21% |
| Middle year built | 1974 | 1978 |
| Owner-occupied | 77% | 68% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.