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 Shannon County, Missouri
EPA puts Shannon County in Zone 2, its middle radon zone, and only 4 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
Highest bordering
45.7%
Howell County
- Howell
- 45.7%
- Texas
- 19.3%
2 of 6 neighbours have 30+ tests, 2008 to 2017
Nearest county
19.3%
Texas County, 33 miles
- Texas
- 19.3%
- Missouri
- 30.6%
Share at 4+ pCi/L, 57 tests, 2008 to 2017
Ground above low
100.0%
5.8 pts above Missouri
- Shannon
- 100.0%
- Missouri
- 94.2%
Share of land USGS rates moderate or high potential
Tests reported
19
Too few for a share
- Shannon
- 19
- 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 Shannon 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
Shannon County, At a glance
Shannon County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Shannon 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 Shannon County, 2022
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 0.0% |
| 2015 | 0.0% |
| 2016 | 100.0% |
| 2018 | 50.0% |
| 2020 | 100.0% |
| 2022 | 0.0% |
2022: 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 4 tests were reported to CDC for Shannon 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: 2005 to 2022 (every CDC figure on file).
Shannon County, Compared
Shannon County radon figures, compared
Calculated by Radon411CDC's largest figure for Shannon County rests on 19 tests over the 2008 to 2017 laboratory totals, 5 of them at or above 4 pCi/L, so each test moves its share by 5.3 points and no rank or comparison is drawn from it. Results reached as high as 9.1 pCi/L, with a middle value of 1.3 pCi/L.
Of the counties bordering it, 2 have a figure over the 2008 to 2017 laboratory totals: Howell County reported the largest share at or above 4 pCi/L, 45.7%, and Texas County the smallest, 19.3%. Farther out, Phelps County (54 miles away) at 14.7%, Crawford County (57 miles away) at 14.7% and Washington County (62 miles away) at 26.3% 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 Shannon County in Zone 2, its middle label: a predicted county average between 2 and 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Shannon County, Geology
The ground under Shannon County
PredictedUSGS's geologic map puts all of Shannon County's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Salem Plateau, 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 |
|---|---|---|---|---|
| Salem Plateau | Ordovician dolomite, sandstone, limestone, and shale. | Moderate | 11 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Shannon County beside the ground around it
Across Missouri 8.2% of the land is rated high; none of Shannon County's is. Of the 6 counties that border it, 1 has more high-potential ground, Reynolds County the most at 14.5%.
The map rates the ground, not the air in any home.
Local help
Shannon County, Local resources
Radon testing and mitigation in Shannon 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
Shannon County, Questions
Questions about radon in Shannon County
Are radon levels high in Shannon County?
In 2022, 0.0% of the radon tests reported to CDC for Shannon County, Missouri were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.2 pCi/L. Of the counties bordering it, 2 have a figure over the 2008 to 2017 laboratory totals: Howell County reported the largest share at or above 4 pCi/L, 45.7%, and Texas County the smallest, 19.3%.
Which counties border Shannon County?
Shannon County borders 6 counties: Reynolds County, Carter County, Oregon County, Dent County, Texas County and Howell County.
Products
Shannon County, Products
Testing a home in Shannon County
No CDC figure names Shannon County; the nearest county with one, Texas County (33 miles away), reported 19.3% 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 Shannon 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
MonitorPYZYCKYH
RD17 plug-in radon detector with a rechargeable battery and color screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Shannon County, Bordering counties
Counties bordering Shannon County
Calculated by Radon411- Radon levels in Howell CountyEPA zone 2
45.7%at or above 4 pCi/L
Median 3.5 pCi/L · 138 tests
- Radon levels in Dent CountyEPA zone 2
35.7%at or above 4 pCi/L
Median 3.0 pCi/L · 14 tests
- Radon levels in Reynolds CountyEPA zone 2
33.3%at or above 4 pCi/L
Median 2.2 pCi/L · 3 tests
- Radon levels in Oregon CountyEPA zone 2
33.3%at or above 4 pCi/L
Median 2.0 pCi/L · 3 tests
- Radon levels in Carter CountyEPA zone 2
25.0%at or above 4 pCi/L
Median 2.8 pCi/L · 4 tests
- Radon levels in Texas CountyEPA zone 2
19.3%at or above 4 pCi/L
Median 1.3 pCi/L · 57 tests
Shannon County, Cities and towns
Cities and towns in Shannon County
The Census Bureau estimates 7,285 residents in Shannon County for July 1, 2025, 251 more than in 2020 (+3.6%). Spread over its land, that is 7.3 people to the square mile. No town dominates: Winona, the largest, has 987 residents, 13.5% of the total. Reported testing is thin here: 19 tests over 2008 to 2017, or 2.6 for every 1,000 residents (2025 estimate), where Missouri as a whole comes to 9.3.
From Winona to Summersville, CDC publishes no figure by town: each reads Shannon County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Winona | 987 | +3.4% | 13.5% |
| Birch Tree | 561 | +3.1% | 7.7% |
| Eminence | 532 | +3.1% | 7.3% |
| Summersvilleextends beyond Shannon County | 474 | +5.6% | Counted whole |
4 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). A place that extends beyond Shannon County is counted whole, so it has no share.
Shannon County, Homes
Homes in Shannon County
Shannon County is a place of houses on their own lots: 82% of its 3,522 homes are detached single-family houses, against 70% across Missouri. Half of its homes were built before 1982, close to Missouri's 1978: 22% date from before 1960 and 23% from 2000 or later. Owners live in 83% of the occupied homes (Missouri: 68%), so for most households a test and a fix are their own to order.
| Homes | Shannon County | Missouri |
|---|---|---|
| Housing units | 3,522 | 2,809,501 |
| Detached houses | 82% | 70% |
| In buildings of 5 or more | 1% | 13% |
| Mobile homes | 13% | 5% |
| Built before 1960 | 22% | 28% |
| Built since 2000 | 23% | 21% |
| Middle year built | 1982 | 1978 |
| Owner-occupied | 83% | 68% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.