Locations and reports
Radon Levels in Clay County, Iowa
What this means for you
- Your area: EPA rates Clay County Zone 1, the highest 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 744 radon tests reported to CDC for Clay County (2008 to 2017), 79.4% 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.
Over the 2008 to 2017 laboratory totals, 79.4% of the radon tests reported to CDC for Clay County, Iowa came back at or above the EPA action level of 4 pCi/L, and the median result was 9.6 pCi/L. EPA's Map of Radon Zones places the county in Zone 1, highest predicted potential. Radon levels vary from home to home, so only a test measures the level in yours.
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA predicts an average indoor of greater than 4 pCi/L (greater than 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: Low across 100% of the county's land area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Clay County, 2008 to 2017, laboratory
- Tests reported
- 744
- At or above 4 pCi/L
- 79.4%
- Median result
- 9.6 pCi/L
Of 744 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 | 95 | 12.8% |
| 2 to 4 pCi/L | 58 | 7.8% |
| 4 pCi/L and above | 591 | 79.4% |
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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Clay County, In figures
Clay County in figures
What the published data says about Clay County, in words. A zone and a share of tests describe an area, never the level in any one home.
Predicted
PredictedEPA places Clay County in Zone 1, highest predicted potential, as it does 98 other counties of Iowa's 99.
Of the 8 bordering counties, EPA places Buena Vista County, Cherokee County, Dickinson County, Emmet County, O'Brien County, Osceola County, Palo Alto County and Pocahontas County in Zone 1.
Reported tests
MeasuredCDC publishes no annual figure for Clay County; its figure is a laboratory total for 2008 to 2017: 79.4% of 744 reported tests were at or above 4 pCi/L.
Local record
Iowa's radon program is the Iowa HHS Radon Program, run by Iowa Department of Health and Human Services; its contacts are under Local resources.
The county's largest incorporated places are Spencer, Everly and Royal; the figures here cover them as part of the county.
Clay County, Comparison
How Clay County compares
MeasuredClay 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
Measured2008 to 2017, laboratory, highest first. Each county’s own published CDC figure.
- O'Brien CountyIA652 tests81.7%
- Clay CountyThis page744 tests79.4%
- Cherokee CountyIA795 tests74.5%
- Buena Vista CountyIA688 tests72.1%
- Emmet CountyIA420 tests71.0%
- Palo Alto CountyIA462 tests70.8%
- Dickinson CountyIA831 tests70.3%
- Pocahontas CountyIA417 tests68.8%
- Osceola CountyIA122 tests67.2%
Median reported result
Measured2008 to 2017, laboratory, highest first. Each county’s own published CDC figure.
- Clay CountyThis page744 tests9.6 pCi/L
- O'Brien CountyIA652 tests8.9 pCi/L
- Cherokee CountyIA795 tests7.6 pCi/L
- Dickinson CountyIA831 tests7.0 pCi/L
- Buena Vista CountyIA688 tests6.9 pCi/L
- Osceola CountyIA122 tests6.8 pCi/L
- Pocahontas CountyIA417 tests6.4 pCi/L
- Emmet CountyIA420 tests6.3 pCi/L
- Palo Alto CountyIA462 tests5.9 pCi/L
Each figure is that county’s own published CDC figure for 2008 to 2017, laboratory, counting radon tests reported to CDC, not homes. Clay 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. Every Iowa county’s own figure is in the Iowa county table.
CDC publishes this figure only for counties here, so there is no state or national number to compare Clay County, Iowa with.
Clay County, Bordering counties
Counties bordering Clay County
Calculated by Radon4118 counties share a boundary with Clay 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.
- Dickinson CountyIAZone 1: Highest predicted potential
- Palo Alto CountyIAZone 1: Highest predicted potential
- Buena Vista CountyIAZone 1: Highest predicted potential
- O'Brien CountyIAZone 1: Highest predicted potential
- Emmet CountyIAZone 1: Highest predicted potential
- Osceola CountyIAZone 1: Highest predicted potential
- Pocahontas CountyIAZone 1: Highest predicted potential
- Cherokee CountyIAZone 1: Highest predicted potential
Clay County, Local resources
Local resources in Iowa
Who to ask in Iowa: the state's radon program, test kits and professionals.
Iowa HHS Radon Program
Iowa Department of Health and Human Services
Iowa’s radon program answers questions about testing, mitigation and the rules where you live.
- Phone
- (515) 281-4928
- Licensing of radon professionals
Iowa’s radon program approves applications for persons who wish to become certified to perform radon testing or credentialed to perform mitigation and laboratories that provide radon testing devices and analytical services.
- Disclosure when a home is sold or rented
However, per Iowa Code chapters 543B.9 and 543B.18 and Iowa Administrative Code 193E Chapter 14 administered by the Iowa Real Estate Commission, a seller must disclose any known tests for the presence of radon and if yes, provide the date of last report and the result(s).
Test kits
The program says: You can reach the Hotline by calling 1-800-383-5992 to order low-cost radon test kits and find answers to your radon questions.
Radon professionals
210 professionals are listed in Iowa.
Professionals in IowaClay County, Cities and towns
Cities and towns in Clay County
The radon figures on this page are for Clay County as a whole. They do not differ by city or town.
- Spencer
- Everly
- Royal
- Peterson
- Fostoria
- Dickens
- Webb
- Greenville
- Rossie
- Gillett Grove
10 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files.
Clay County, Questions
Questions about radon in Clay County
Common questions8 questions, answered from the figures above
Are radon levels high in Clay County?
In 2017, 79.4% of the radon tests reported to CDC for Clay County, Iowa were at or above 4 pCi/L, and the median reported pre-mitigation result was 9.6 pCi/L. That is a share of reported tests, not of homes. EPA places Clay County in Zone 1, highest predicted potential, a predicted average indoor screening level greater than 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 Clay 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 Clay County as a service area yet. The Iowa 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 stateIowa radon program
Who does radon mitigation in Clay County?
No listed mitigator names Clay County as a service area yet; the Iowa directory lists 210 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 Iowa requires one.
How radon mitigation worksWhat mitigation costsMitigators in Iowa
What EPA radon zone is Clay County in?
EPA places Clay County, Iowa in Zone 1, which EPA describes as highest 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 Clay 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 Clay County?
Clay County borders 8 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 Clay County, Iowa in 2017. 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.
Clay County, Products
Testing and mitigation products
Whatever the figures for Clay 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.
Clay 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.