Locations and reports
Radon Levels in Phelps County, Missouri
What this means for you
- Your area: EPA rates Phelps County Zone 2, the middle of its three radon zones. That is a prediction for the whole county, and homes with elevated levels occur in all three zones.
- Local tests: Of 4 radon tests reported to CDC for Phelps County (2023), 25.0% were at or above 4 pCi/L, EPA's action level.
- Your home: The only way to know your home’s level is to test it.
pCi/L (picocuries per liter) is the unit radon is measured in. EPA recommends fixing a home at 4 pCi/L or above, its action level.
In 2023, 25.0% of the radon tests reported to CDC for Phelps County, Missouri came back at or above the EPA action level of 4 pCi/L, and the median result was 2.0 pCi/L. EPA's Map of Radon Zones places the county in Zone 2, moderate predicted potential. Radon levels vary from home to home, so only a test measures the level in yours.
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
EPA predicts an average indoor of 2 to 4 pCi/L (75 to 150 Bq/m³) across the county as a whole.
This is a county-level geologic prediction. It is not a measurement of any address, and houses with elevated radon are found in all three zones.
USGS geologic potential: Moderate across 100% of the county's land area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Phelps County, 2023
- Tests reported
- 4
- At or above 4 pCi/L
- 25.0%
- Median result
- 2.0 pCi/L
Of 4 pre-mitigation tests reported to CDC, not homes in this area. CDC publishes the share in each band, not a count per band, so the per-band counts in the table are calculated by Radon411 and rounded to add up to the published total.
| Result band | Tests Calculated by Radon411 | Share Measured |
|---|---|---|
| Under 2 pCi/L | 2 | 50.0% |
| 2 to 4 pCi/L | 1 | 25.0% |
| 4 pCi/L and above | 1 | 25.0% |
Distribution of tested buildings, not this house. People testing before a sale, or because they suspect a problem, are over-represented in any reported testing data.
Measured: CDC tracking data. Figure above: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
Phelps County, In figures
Phelps County in figures
What the published data says about Phelps County, in words. A zone and a share of tests describe an area, never the level in any one home.
Predicted
PredictedEPA places Phelps County in Zone 2, moderate predicted potential, as it does 96 other counties of Missouri's 115.
Of the 6 bordering counties, EPA places Crawford County, Dent County, Gasconade County, Maries County, Pulaski County and Texas County in Zone 2.
Reported tests
MeasuredCDC has annual figures for Phelps County for 10 years, 2014 to 2023. In 2023, 25.0% of 4 reported tests were at or above 4 pCi/L.
Across those years the share ranged from 0.0% (2020) to 50.0% (2021). Few tests in a year can move it a long way.
Local record
Missouri's radon program is the Missouri Radon Program, run by Missouri Department of Health and Senior Services; its contacts are under Local resources.
The county's largest incorporated places are Rolla, St. James and Doolittle; the figures here cover them as part of the county.
Phelps County, Reported testing
Reported testing over time
Measured| Year | Median reported result | Highest reported result | Share of tests at or above 4 pCi/L |
|---|---|---|---|
| 2014 | 1.6 pCi/L | 3.8 pCi/L | 0.0% |
| 2015 | 1.0 pCi/L | 5.1 pCi/L | 10.5% |
| 2016 | 1.6 pCi/L | 4.3 pCi/L | 4.3% |
| 2017 | 3.2 pCi/L | 8.3 pCi/L | 28.6% |
| 2018 | 10.7 pCi/L | 19.2 pCi/L | 50.0% |
| 2019 | 2.8 pCi/L | 2.8 pCi/L | 0.0% |
| 2020 | 1.9 pCi/L | 1.9 pCi/L | 0.0% |
| 2021 | 4.9 pCi/L | 9.2 pCi/L | 50.0% |
| 2022 | 2.6 pCi/L | 7.7 pCi/L | 33.3% |
| 2023 | 2.0 pCi/L | 7.4 pCi/L | 25.0% |
What these figures count
Every percentage here is a share of radon tests reported to CDC for Phelps County in 2023. It is not a share of homes in Phelps County, and it is not a random sample: it counts only the tests people chose to run and that were reported.
The shares and the median are calculated from pre-mitigation tests (4 for 2023).
Phelps County, Comparison
How Phelps County compares
MeasuredPhelps County's own published CDC figures beside those of the counties that border it, for the same period.
Share of reported tests at or above 4 pCi/L
Measured2023, highest first. Each county’s own published CDC figure.
- Crawford CountyMOTest count not published100.0%
- Dent CountyMO4 tests50.0%
- Gasconade CountyMOTest count not published50.0%
- Texas CountyMOTest count not published50.0%
- Phelps CountyThis page4 tests25.0%
- Pulaski CountyMO5 tests20.0%
Median reported result
Measured2023, highest first. Each county’s own published CDC figure.
- Gasconade CountyMOTest count not published11.1 pCi/L
- Crawford CountyMOTest count not published7.3 pCi/L
- Dent CountyMO4 tests4.3 pCi/L
- Texas CountyMOTest count not published3.7 pCi/L
- Pulaski CountyMO5 tests2.4 pCi/L
- Phelps CountyThis page4 tests2.0 pCi/L
Each figure is that county’s own published CDC figure for 2023, counting radon tests reported to CDC, not homes. Phelps County is this page. Nothing is averaged or combined across counties. The test count beside each county is CDC’s published number of pre-mitigation tests behind its figures. Figures from few tests can swing widely from year to year. No published CDC figure for 2023: Maries County, MO. Every Missouri county’s own figure is in the Missouri county table.
CDC publishes this figure only for counties here, so there is no state or national number to compare Phelps County, Missouri with.
Phelps County, Bordering counties
Counties bordering Phelps County
Calculated by Radon4116 counties share a boundary with Phelps County, computed from Census county geometry. Radon potential follows geology rather than county lines, so a bordering county’s report can be worth reading alongside this one.
- Maries CountyMOZone 2: Moderate predicted potential
- Dent CountyMOZone 2: Moderate predicted potential
- Pulaski CountyMOZone 2: Moderate predicted potential
- Crawford CountyMOZone 2: Moderate predicted potential
- Texas CountyMOZone 2: Moderate predicted potential
- Gasconade CountyMOZone 2: Moderate predicted potential
Phelps County, Local resources
Local resources in Missouri
Who to ask in Missouri: the state's radon program, test kits and professionals.
Missouri Radon Program
Missouri Department of Health and Senior Services
Missouri’s radon program answers questions about testing, mitigation and the rules where you live.
- Phone
- 573-751-6102
- radon@health.mo.gov
Test kits
The program says: Free radon test kits are available for Missouri residents (limit one per household).
Radon professionals
6 professionals are listed in Missouri.
Professionals in MissouriPhelps County, Cities and towns
Cities and towns in Phelps County
The radon figures on this page are for Phelps County as a whole. They do not differ by city or town.
- Rolla
- St. James
- Doolittle
- Newburg
- Edgar Springs
5 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files.
Phelps County, Questions
Questions about radon in Phelps County
Common questions8 questions, answered from the figures above
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. That is a share of reported tests, not of homes. EPA places Phelps County in Zone 2, moderate predicted potential, a predicted average indoor screening level 2 to 4 pCi/L. Homes with elevated levels occur in all three zones, so the figures describe the area, not your house. Testing is the only way to know the radon level in a specific building.
How do I get a radon test in Phelps County?
EPA says you can test your home yourself or hire a qualified radon test company, and that either approach takes only a small amount of time and effort. No certified tester listed on Radon411 names Phelps County as a service area yet. The Missouri radon program is the place to ask about certified testers and any test kit offer it runs.
How to test a homeTest kits comparedFree and low-cost kits by stateMissouri radon program
Who does radon mitigation in Phelps County?
No listed mitigator names Phelps County as a service area yet; the Missouri directory lists 6 companies. EPA recommends having a qualified contractor fix a home with a radon problem, because lowering high radon levels takes technical knowledge and special skills, and some states require the work to be done by a licensed or certified professional. Your state radon program is the place to check whether Missouri requires one.
How radon mitigation worksWhat mitigation costsMitigators in Missouri
What EPA radon zone is Phelps County in?
EPA places Phelps County, Missouri in Zone 2, which EPA describes as moderate predicted potential for the area. A zone is a prediction for the whole county and never determines whether a particular home should be tested. EPA recommends testing every home regardless of zone.
Should I test my home in Phelps County?
Yes. Testing is the only way to know the radon level in a specific building. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. How to test a home.
When is the best time of year to test?
EPA says short-term tests stay in the home from 2 to 90 days and that all radon tests should run a minimum of 48 hours; long-term tests stay more than 90 days. EPA's guides do not name a best season: they say radon levels tend to vary from day to day and season to season, so a long-term test is more likely than a short-term test to tell you the year-round average.
What does it cost to test?
EPA's Citizen's Guide calls testing easy and inexpensive, and EPA's Home Buyer's and Seller's Guide says passive short-term and long-term devices are generally inexpensive, while active devices may cost more. No national average price is published for this, so Radon411 does not give one. What testing costs.
Which counties border Phelps County?
Phelps County borders 6 counties, derived from Census county geometry. Radon potential follows geology rather than county lines, so a bordering county's report can be relevant.
What these figures mean if you own, buy, sell or rent
The reported-test figures on this page describe Phelps County, Missouri in 2023. They describe tests other people carried out in other buildings, and none of them measures yours.
- How to test a home
If you own your home
Test the lowest lived-in level; a short-term kit screens in days, a long-term kit reflects the year.
- Buying a house: radon guide
If you are buying
Ask for past results and any system's post-mitigation test, and test during the sale.
- Selling a house: radon guide
If you are selling
Testing before you list puts the timing in your hands; disclosure rules differ by state.
- Radon in rental homes
If you rent, or rent out a home
A tenant can test; a fix is the owner's to make, and duties differ by state.
How long a test has to run, under what conditions, and what EPA says a result means: the testing standard, in full.
Phelps County, Products
Testing and mitigation products
Whatever the figures for Phelps County show, only a test tells you about one home.
Testing
- Short-term test kitsPassive detectors exposed for a few days under closed-building conditions, then analyzed by a lab.
- Long-term test kitsDetectors exposed for more than 90 days, for a closer picture of the annual average.
- Continuous monitorsPowered devices that log radon on a repeating cycle, often used for transaction tests.
- Digital detectorsConsumer devices that display a running radon reading without a lab.
- Water radon testsKits for radon dissolved in well water, analyzed by a lab.
Mitigation
- Mitigation fansThe inline fan that keeps a soil depressurization system running, sized by the installer.
- System indicatorsU-tube manometers and fan alarms that show whether a mitigation system is still working.
- Sealing materialsCrack, joint and sump sealing used alongside a mitigation system, not instead of one.
Phelps County / Next steps
What to do next
Learn
Know what radon is
What radon is, how it gets indoors, and why a county zone is not a reading for your home.
Learn about radonTest
Test the building you live in
Short-term or long-term, where the device goes, and closed-house conditions.
How to testFix
Bring a high level down
How a mitigation system works, and the retest that confirms it.
How mitigation worksFind a pro
Hire a certified professional
Measurement and mitigation professionals by state, with their certifications.
Find a professional
Informational. Follow EPA guidance. EPA says all radon tests should be taken for a minimum of 48 hours, with windows and doors closed from 12 hours before a short-term test.