60%tests ≥ 4 pCi/L
1,285tests on record
4.8median pCi/L
Zone 1EPA zone (1993 prediction)

Test results in Union County

ResultShareEPA guidance
Below 2 pCi/L13%Below EPA's levels
2 to 4 pCi/L27%Consider fixing
4 pCi/L or more60%EPA recommends fixing

What the data shows

Where Union 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 Union County compares

Union County ranks 7 of 8 among its neighboursShare of tests at or above 4 pCi/L · Radon test results from laboratories, 2008–2017 · whisker: 95% range
Logan County74%Delaware County72%Franklin County72%Champaign County71%Madison County67%Marion County65%Union County60%Hardin County43%Ohio 52%
Data table
AreaTests ≥ 4 pCi/LTests
Logan County74%755
Delaware County72%3,730
Franklin County72%16,142
Champaign County71%596
Madison County67%549
Marion County65%265
Union County60%1,285
Hardin County43%67
Ohio (88 counties)52%98,840

Same source as Union County.

What it means for your home

More than half of all results in Union 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.

Prefer a digital monitor? See Airthings radon monitors, or enter code radonbycounty-10OFF at their discount store for 10% off.

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: 1,285. 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