49%tests ≥ 4 pCi/L
70tests on record
3.8median pCi/L
Zone 2EPA zone (1993 prediction)

Test results in Defiance County

ResultShareEPA guidance
Below 2 pCi/L23%Below EPA's levels
2 to 4 pCi/L29%Consider fixing
4 pCi/L or more49%EPA recommends fixing

What the data shows

Where Defiance County sits among Ohio's 88 counties with dataEach dot is a county's share of tests at or above 4 pCi/L · Radon test results from laboratories, 2008–2017
0%20%40%60%80%

How Defiance County compares

Defiance County ranks 4 of 7 among its neighboursShare of tests at or above 4 pCi/L · Radon test results from laboratories, 2008–2017 · whisker: 95% range
Henry County62%Putnam County60%DeKalb County, Indiana57%Defiance County49%Williams County43%Allen County, Indiana42%Paulding County23%Ohio 52%
Data table
AreaTests ≥ 4 pCi/LTests
Henry County62%34
Putnam County60%94
DeKalb County, Indiana57%242
Defiance County49%70
Williams County43%28
Allen County, Indiana42%3,990
Paulding County23%13
Ohio (88 counties)52%98,840

Same source as Defiance County.

What it means for your home

About 1 in 2 results in Defiance 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 →

About this data

Source: Radon test results from laboratories (CDC Environmental Public Health Tracking Network). Period: 2008–2017. Tests: 70. 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