Short-term kit
PicoCan short-term charcoal canister radon test
- Lab fee included
Method: Charcoal
In home: 48 to 96 hours
Locations and reports
Radon Levels in Phelps County, Missouri
EPA puts Phelps County in Zone 2, its middle radon zone, and only 4 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
14.7%
15.9 pts below MO
- Phelps
- 14.7%
- Missouri
- 30.6%
204 tests, 2008 to 2017
Median result
1.5pCi/L
Below action level
- Phelps
- 1.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
204
23rd of 72 by tests
- Phelps
- 204
- 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
68 of 72
Lowest quarter
- Phelps
- 14.7%
- Atchison
- 69.9%
By share, of 72 with 30+ tests
Read a result for Phelps County
Starts at Phelps County's median, 1.5 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.5 pCi/L
Below 2 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is below 2 pCi/L, the level at which EPA says a fix should be considered. Phelps County's median reported result, 2008 to 2017.
The data
Phelps County, At a glance
Phelps County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Phelps 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 Phelps County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 0.0% |
| 2015 | 10.5% |
| 2016 | 4.3% |
| 2017 | 28.6% |
| 2018 | 50.0% |
| 2019 | 0.0% |
| 2020 | 0.0% |
| 2021 | 50.0% |
| 2022 | 33.3% |
| 2023 | 25.0% |
2023: 25.0%. 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 4 tests were reported to CDC for Phelps 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).
Phelps County, Compared
Phelps County radon figures, compared
Calculated by Radon411Phelps County reports fewer high tests than Missouri overall. 14.7% of its 204 tests over the 2008 to 2017 laboratory totals were at or above 4 pCi/L. That is 15.9 points below the 30.6% pooled from 115 Missouri counties.
The newest figure, in 2023, counts only 4 tests (25.0% at or above 4 pCi/L), too few to compare, so this reading uses the 204-test figure.
Ordered from highest share down, it comes 68th of 72 Missouri counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 35.7%; Phelps County sits 21.0 points below it.
Next door, the shares run from 14.7% in Crawford County to 31.8% in Gasconade County. Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 14.7% share point the same way here.
Half the tests came in under 1.5 pCi/L and half over it; the single highest reached 20.3 pCi/L. The rest split 62.7% under 2 pCi/L and 22.5% from 2 to 4 (Missouri: 41.2% and 28.1%).
The busiest year on file was 2016, with 23 tests reported; the quietest, 2020, had 1.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Phelps County, Geology
The ground under Phelps County
PredictedUSGS's geologic map puts all of Phelps 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.
Phelps County beside the ground around it
Across Missouri 8.2% of the land is rated high; none of Phelps County's is. Of the 6 counties that border it, none has as large a share of moderate-potential ground; Crawford County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Phelps County, Local resources
Radon testing and mitigation in Phelps 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
Phelps County, Questions
Questions about radon in Phelps County
Are radon levels high in Phelps County?
In 2023, 25.0% of the radon tests reported to CDC for Phelps 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, 67 reported a higher share; pooled, the state comes to 30.6%.
Which counties border Phelps County?
Phelps County borders 6 counties: Maries County, Dent County, Pulaski County, Crawford County, Texas County and Gasconade County.
Products
Phelps County, Products
Testing a home in Phelps County
In Phelps County, 14.7% of 204 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 Phelps 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
Monitor
RadonScan-Plus USB-powered radon monitor with Wi-Fi
- C-NRPP 2024/25: Not included
- Plug-in
- Wi-Fi
- Alarm
- Screen, app
First reading: Within 5 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Phelps County, Bordering counties
Counties bordering Phelps County
Calculated by Radon411- Radon levels in Dent CountyEPA zone 2
35.7%at or above 4 pCi/L
Median 3.0 pCi/L · 14 tests · 21.0 points above Phelps County
- Radon levels in Gasconade CountyEPA zone 2
31.8%at or above 4 pCi/L
Median 2.3 pCi/L · 44 tests · 17.1 points above Phelps County
- Radon levels in Texas CountyEPA zone 2
19.3%at or above 4 pCi/L
Median 1.3 pCi/L · 57 tests · 4.6 points above Phelps County
- Radon levels in Pulaski CountyEPA zone 2
18.7%at or above 4 pCi/L
Median 1.3 pCi/L · 107 tests · 4.0 points above Phelps County
- Radon levels in Crawford CountyEPA zone 2
14.7%at or above 4 pCi/L
Median 1.5 pCi/L · 34 tests · 0.0 points above Phelps County
- Radon levels in Maries CountyEPA zone 2
14.3%at or above 4 pCi/L
Median 1.8 pCi/L · 21 tests · 0.4 points below Phelps County
Phelps County, Cities and towns
Cities and towns in Phelps County
The Census Bureau estimates 45,247 residents in Phelps County for July 1, 2025, 694 more than in 2020 (+1.6%). That works out to 67 people per square mile of land. Its largest town, Rolla, has 20,588 residents, 45.5% of the total. Together its 5 incorporated places hold 56.6% of those residents; the other 43.4% live outside any of them. Reported testing is thin here: 204 tests over 2008 to 2017, or 4.5 for every 1,000 residents (2025 estimate), where Missouri as a whole comes to 9.3.
From Rolla to Edgar Springs, CDC publishes no figure by town: each reads Phelps County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Rolla | 20,588 | +3.4% | 45.5% |
| St. James | 3,925 | +0.7% | 8.7% |
| Doolittle | 565 | Level | 1.2% |
| Newburg | 331 | −1.2% | 0.7% |
| Edgar Springs | 196 | −0.5% | 0.4% |
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).
Phelps County, Homes
Homes in Phelps County
Of Phelps County's 20,246 homes, 64% are detached houses, against 70% across Missouri; 11% are in buildings of five or more homes. Half of its homes were built before 1984, close to Missouri's 1978: 18% date from before 1960 and 26% from 2000 or later. 62% of occupied homes are lived in by their owner (Missouri: 68%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Phelps County | Missouri |
|---|---|---|
| Housing units | 20,246 | 2,809,501 |
| Detached houses | 64% | 70% |
| In buildings of 5 or more | 11% | 13% |
| Mobile homes | 9% | 5% |
| Built before 1960 | 18% | 28% |
| Built since 2000 | 26% | 21% |
| Middle year built | 1984 | 1978 |
| Owner-occupied | 62% | 68% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.