Short-term kit
RA100 short-term liquid scintillation radon test kit
- Lab fee extra
Method: Liquid scintillation
In home: 48 to 96 hours
Locations and reports
Radon Levels in Ripley County, Missouri
EPA puts Ripley County in Zone 2, its middle radon zone, and only 1 radon test from it is on file with CDC (2018). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Highest bordering
21.2%
Butler County
- Butler
- 21.2%
1 of 5 neighbours have 30+ tests, 2008 to 2017
Nearest county
21.2%
Butler County, 26 miles
- Butler
- 21.2%
- Missouri
- 30.6%
Share at 4+ pCi/L, 33 tests, 2008 to 2017
Ground above low
90.3%
3.9 pts below Missouri
- Ripley
- 90.3%
- Missouri
- 94.2%
Share of land USGS rates moderate or high potential
Tests reported
10
Too few for a share
- Ripley
- 10
- Needed
- 30
2008 to 2017, laboratory
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 Ripley 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
Ripley County, At a glance
Ripley County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Ripley County is a
USGS geologic potential: Moderate across 90% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Ripley County, 2018
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2015 | 100.0% |
| 2016 | 0.0% |
| 2017 | 50.0% |
| 2018 | 0.0% |
2018: 0.0%. Across these years the share ran from 0.0% to 100.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 1 test was reported to CDC for Ripley County over 2018, 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: 2018. Measured data period: 2005 to 2018 (every CDC figure on file).
Ripley County, Compared
Ripley County radon figures, compared
Calculated by Radon411CDC's largest figure for Ripley County rests on 10 tests over the 2008 to 2017 laboratory totals, 3 of them at or above 4 pCi/L, so each test moves its share by 10.0 points and no rank or comparison is drawn from it. Results reached as high as 20.0 pCi/L, with a middle value of 3.0 pCi/L.
Butler County, the one bordering county with a figure over the 2008 to 2017 laboratory totals, reported 21.2% of its tests at or above 4 pCi/L. Farther out, Howell County (57 miles away) at 45.7%, Texas County (76 miles away) at 19.3% and Scott County (77 miles away) at 29.4% have figures too. Pooled across 115 Missouri counties, 30.6% of reported tests reached that level; across every county in the country with a figure, 35.7%.
Statewide for the same period, Atchison County reported the highest share (69.9%) and Vernon County the lowest (8.8%). EPA's 1993 map puts Ripley County in Zone 2, its middle label: a predicted county average between 2 and 4 pCi/L. USGS geology rates 90% of the county's land moderate radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Ripley County, Geology
The ground under Ripley County
PredictedMost of the ground under Ripley County is one class on USGS's geologic map: 90.3% of its land is moderate radon potential, with 9.7% low. The map puts 90.3% of Ripley County in the area it calls Salem Plateau and 9.7% in Coastal Plains Province. USGS gives the first a radon index of 11, in the moderate band (9 to 11), and the second 5, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Salem Plateau | Ordovician dolomite, sandstone, limestone, and shale. | Moderate | 11 | 90.3% |
| Coastal Plains Province | Tertiary-Quaternary sandstone, shale, and alluvium. | Low | 5 | 9.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Ripley County beside the ground around it
Across Missouri 8.2% of the land is rated high; none of Ripley County's is. Of the 5 counties that border it, 2 have more moderate-potential ground, Carter County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Ripley County, Local resources
Radon testing and mitigation in Ripley 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
Ripley County, Questions
Questions about radon in Ripley County
Are radon levels high in Ripley County?
In 2018, 0.0% of the radon tests reported to CDC for Ripley County, Missouri were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.5 pCi/L. Butler County, the one bordering county with a figure over the 2008 to 2017 laboratory totals, reported 21.2% of its tests at or above 4 pCi/L.
Which counties border Ripley County?
Ripley County borders 5 counties: Carter County, MO, Randolph County, AR, Butler County, MO, Oregon County, MO and Clay County, AR.
Products
Ripley County, Products
Testing a home in Ripley County
No CDC figure names Ripley County; the nearest county with one, Butler County (26 miles away), reported 21.2% of its tests at or above 4 pCi/L over the 2008 to 2017 laboratory totals, 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 Ripley 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
MonitorAEGTEST
HOUND-3699 radon monitor with a 2.1-inch touchscreen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
First reading: Within 1 hour
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Ripley County, Bordering counties
Counties bordering Ripley County
Calculated by Radon411- Radon levels in Randolph County, AREPA zone 2
50.0%at or above 4 pCi/L
Median 3.2 pCi/L · 2 tests
- Radon levels in Oregon County, MOEPA zone 2
33.3%at or above 4 pCi/L
Median 2.0 pCi/L · 3 tests
- Radon levels in Carter County, MOEPA zone 2
25.0%at or above 4 pCi/L
Median 2.8 pCi/L · 4 tests
- Radon levels in Butler County, MOEPA zone 3
21.2%at or above 4 pCi/L
Median 1.9 pCi/L · 33 tests
- Radon levels in Clay County, AREPA zone 3
0.0%at or above 4 pCi/L
Median 0.2 pCi/L · 1 test
Ripley County, Cities and towns
Cities and towns in Ripley County
Ripley County's population has barely moved since 2020: 10,717 residents on July 1, 2025 against 10,670 then, by the Census Bureau's estimates. That works out to 17 people per square mile of land. No town dominates: Doniphan, the largest, has 1,784 residents, 16.6% of the total. Together its 2 incorporated places hold 20.7% of those residents; the other 79.3% live outside any of them. Reported testing is thin here: 10 tests over 2008 to 2017, or 0.9 for every 1,000 residents (2025 estimate), where Missouri as a whole comes to 9.3.
From Doniphan to Naylor, CDC publishes no figure by town: each reads Ripley County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Doniphan | 1,784 | +0.1% | 16.6% |
| Naylor | 435 | −1.4% | 4.1% |
2 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).
Ripley County, Homes
Homes in Ripley County
Of Ripley County's 5,191 homes, 73% are detached houses, against 70% across Missouri; 21% are mobile homes. Half of its homes were built before 1983, close to Missouri's 1978: 15% date from before 1960 and 24% from 2000 or later. Owners live in 79% of the occupied homes (Missouri: 68%), so for most households a test and a fix are their own to order.
| Homes | Ripley County | Missouri |
|---|---|---|
| Housing units | 5,191 | 2,809,501 |
| Detached houses | 73% | 70% |
| In buildings of 5 or more | 2% | 13% |
| Mobile homes | 21% | 5% |
| Built before 1960 | 15% | 28% |
| Built since 2000 | 24% | 21% |
| Middle year built | 1983 | 1978 |
| Owner-occupied | 79% | 68% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.