Test results in Clayton County
| Result | Share | EPA guidance |
|---|---|---|
| Below 2 pCi/L | 17% | Below EPA's levels |
| 2 to 4 pCi/L | 21% | Consider fixing |
| 4 pCi/L or more | 63% | EPA recommends fixing |
What the data shows
- Higher share of high results than 44 of 99 Iowa counties.
- Higher than 3 of 6 neighbouring counties.
- 83% of results at or above 2 pCi/L.
- 35.2 tests per 1,000 homes (Iowa: 66.2).
- Median result 5.8 pCi/L: at or above the 4 pCi/L action level.
How Clayton County compares
Data table
| Area | Tests ≥ 4 pCi/L | Tests |
|---|---|---|
| Allamakee County | 73% | 492 |
| Winneshiek County | 66% | 1,071 |
| Fayette County | 63% | 746 |
| Clayton County | 63% | 310 |
| Buchanan County | 51% | 564 |
| Delaware County | 50% | 520 |
| Dubuque County | 47% | 3,775 |
| Iowa (99 counties) | 58% | 95,245 |
Same source as Clayton County. Other bordering counties: Crawford County, Wisconsin, Grant County, Wisconsin.
What it means for your home
More than half of all results in Clayton County were at or above 4 pCi/L, where the EPA recommends a fix. Only a test shows your own home's level.
Levels in pCi/L from the EPA. The WHO reference level is 100 Bq/m³, about 2.7 pCi/L.
Test your home
Start with a short-term test (2–90 days) and confirm a result of 4 pCi/L or more with a second test. EPA guide
Sponsored: we earn a commission on purchases through these links. We haven't tested Airthings monitors yet.
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Fixing high radon
No local job records yet. National range: $800–$2,500, average $1,200 (EPA, 2003). Cost guide →
Iowa licenses radon mitigators. Source
Buying or selling here
Iowa sellers complete the Real Estate Commission's disclosure statement and must give buyers the "Iowa Radon Home-Buyers and Sellers Fact Sheet" (Iowa Admin. Code 193E). Source
Checked against the official text on 2026-11-03. Not legal advice.
About this data
Source: Iowa radon test results from laboratories (CDC Environmental Public Health Tracking Network). Period: 2008–2017. Tests: 310. Read the methodology →
These are voluntary and real-estate tests, not a random sample of homes, so they describe tested homes rather than every home.
About this page
Published by Ray Roman, editor of Radon by County. Figures are loaded from the cited source and spot-checked against it. Editorial policy · About us