73%tests ≥ 4 pCi/L
313tests on record
6.2median pCi/L
Zone 1EPA zone (1993 prediction)

Test results in Franklin County

ResultShareEPA guidance
Below 2 pCi/L12%Below EPA's levels
2 to 4 pCi/L14%Consider fixing
4 pCi/L or more73%EPA recommends fixing

What the data shows

Where Franklin County sits among Iowa's 99 counties with dataEach dot is a county's share of tests at or above 4 pCi/L · Iowa radon test results from laboratories, 2008–2017
0%20%40%60%80%

How Franklin County compares

Franklin County has the highest share of high results among its neighboursShare of tests at or above 4 pCi/L · Iowa radon test results from laboratories, 2008–2017 · whisker: 95% range
Franklin County73%Grundy County67%Wright County67%Hancock County65%Hamilton County64%Hardin County63%Butler County60%Floyd County60%Cerro Gordo County59%Iowa 58%
Data table
AreaTests ≥ 4 pCi/LTests
Franklin County73%313
Grundy County67%501
Wright County67%292
Hancock County65%640
Hamilton County64%252
Hardin County63%349
Butler County60%377
Floyd County60%697
Cerro Gordo County59%1,662
Iowa (99 counties)58%95,245

Same source as Franklin County.

What it means for your home

More than half of all results in Franklin 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: 313. 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