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 Dallas County, Missouri
EPA puts Dallas County in Zone 2, its middle radon zone, and only 3 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
Highest bordering
37.0%
Laclede County
- Laclede
- 37.0%
- Polk
- 11.5%
5 of 6 neighbours have 30+ tests, 2008 to 2017
Nearest county
11.5%
Polk County, 21 miles
- Polk
- 11.5%
- Missouri
- 30.6%
Share at 4+ pCi/L, 78 tests, 2008 to 2017
Ground above low
100.0%
5.8 pts above Missouri
- Dallas
- 100.0%
- Missouri
- 94.2%
Share of land USGS rates moderate or high potential
Tests reported
29
Too few for a share
- Dallas
- 29
- Needed
- 30
2007 to 2016, 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 Dallas 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
Dallas County, At a glance
Dallas County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Dallas 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 Dallas County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 0.0% |
| 2017 | 0.0% |
| 2018 | 0.0% |
| 2019 | 0.0% |
| 2020 | 33.3% |
| 2021 | 50.0% |
| 2022 | 0.0% |
| 2023 | 33.3% |
2023: 33.3%. Across these years the share ran from 0.0% to 50.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 3 tests were reported to CDC for Dallas 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).
Dallas County, Compared
Dallas County radon figures, compared
Calculated by Radon411CDC's largest figure for Dallas County rests on 29 tests over the 2007 to 2016 laboratory totals, 6 of them at or above 4 pCi/L, so each test moves its share by 3.4 points and no rank or comparison is drawn from it. Results reached as high as 11.0 pCi/L, with a middle value of 1.8 pCi/L.
Of the counties bordering it, 5 have a figure over the 2008 to 2017 laboratory totals: Laclede County reported the largest share at or above 4 pCi/L, 37.0%, and Polk County the smallest, 11.5%, with Greene County at 32.7%, Camden County at 22.9% and Webster County at 20.4% between. Farther out, Benton County (45 miles away) at 30.6%, Pulaski County (46 miles away) at 18.7% and Miller County (49 miles away) at 16.9% 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 Dallas 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.
Dallas County, Geology
The ground under Dallas County
PredictedUSGS's geologic map puts all of Dallas 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.
Dallas County beside the ground around it
Across Missouri 8.2% of the land is rated high; none of Dallas County's is. Of the 6 counties that border it, none has as large a share of moderate-potential ground; Camden County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Dallas County, Local resources
Radon testing and mitigation in Dallas 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
Dallas County, Questions
Questions about radon in Dallas County
Are radon levels high in Dallas County?
In 2023, 33.3% of the radon tests reported to CDC for Dallas County, Missouri were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.8 pCi/L. Of the counties bordering it, 5 have a figure over the 2008 to 2017 laboratory totals: Laclede County reported the largest share at or above 4 pCi/L, 37.0%, and Polk County the smallest, 11.5%, with Greene County at 32.7%, Camden County at 22.9% and Webster County at 20.4% between.
Which counties border Dallas County?
Dallas County borders 6 counties: Webster County, Polk County, Laclede County, Hickory County, Camden County and Greene County.
Products
Dallas County, Products
Testing a home in Dallas County
No CDC figure names Dallas County; the nearest county with one, Polk County (21 miles away), reported 11.5% 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 Dallas 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
MonitorForensics Detectors
FD-65-RADON rechargeable radon detector with a 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
Dallas County, Bordering counties
Counties bordering Dallas County
Calculated by Radon411- Radon levels in Laclede CountyEPA zone 2
37.0%at or above 4 pCi/L
Median 2.3 pCi/L · 46 tests
- Radon levels in Greene CountyEPA zone 2
32.7%at or above 4 pCi/L
Median 2.5 pCi/L · 1,470 tests
- Radon levels in Camden CountyEPA zone 2
22.9%at or above 4 pCi/L
Median 2.2 pCi/L · 763 tests
- Radon levels in Webster CountyEPA zone 2
20.4%at or above 4 pCi/L
Median 1.6 pCi/L · 103 tests
- Radon levels in Polk CountyEPA zone 2
11.5%at or above 4 pCi/L
Median 1.6 pCi/L · 78 tests
- Radon levels in Hickory CountyEPA zone 2
0.0%at or above 4 pCi/L
Median 2.0 pCi/L · 9 tests
Dallas County, Cities and towns
Cities and towns in Dallas County
Dallas County is growing: the Census Bureau puts it at 18,025 residents on July 1, 2025, up 5.2% from 17,133 in 2020. That works out to 33 people per square mile of land. No town dominates: Buffalo, the largest, has 3,550 residents, 19.7% of the total. Together its 3 incorporated places hold 22.8% of those residents; the other 77.2% live outside any of them. Reported testing is thin here: 29 tests over 2007 to 2016, or 1.6 for every 1,000 residents (2025 estimate), where Missouri as a whole comes to 8.8.
From Buffalo to Louisburg, CDC publishes no figure by town: each reads Dallas County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Buffalo | 3,550 | +7.2% | 19.7% |
| Urbana | 411 | +4.3% | 2.3% |
| Louisburg | 140 | +3.7% | 0.8% |
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).
Dallas County, Homes
Homes in Dallas County
Dallas County is a place of houses on their own lots: 79% of its 7,610 homes are detached single-family houses, against 70% across Missouri. Half of its homes were built before 1983, close to Missouri's 1978: 21% date from before 1960 and 26% from 2000 or later. Owners live in 76% of the occupied homes (Missouri: 68%), so for most households a test and a fix are their own to order.
| Homes | Dallas County | Missouri |
|---|---|---|
| Housing units | 7,610 | 2,809,501 |
| Detached houses | 79% | 70% |
| In buildings of 5 or more | 1% | 13% |
| Mobile homes | 15% | 5% |
| Built before 1960 | 21% | 28% |
| Built since 2000 | 26% | 21% |
| Middle year built | 1983 | 1978 |
| Owner-occupied | 76% | 68% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.