65%tests ≥ 4 pCi/L
265tests on record
6.4median pCi/L
Zone 1EPA zone (1993 prediction)

Test results in Marion County

ResultShareEPA guidance
Below 2 pCi/L16%Below EPA's levels
2 to 4 pCi/L19%Consider fixing
4 pCi/L or more65%EPA recommends fixing

What the data shows

Where Marion 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 Marion County compares

Marion County ranks 2 of 7 among its neighboursShare of tests at or above 4 pCi/L · Radon test results from laboratories, 2008–2017 · whisker: 95% range
Delaware County72%Marion County65%Morrow County65%Union County60%Crawford County60%Wyandot County46%Hardin County43%Ohio 52%
Data table
AreaTests ≥ 4 pCi/LTests
Delaware County72%3,730
Marion County65%265
Morrow County65%177
Union County60%1,285
Crawford County60%210
Wyandot County46%320
Hardin County43%67
Ohio (88 counties)52%98,840

Same source as Marion County.

What it means for your home

More than half of all results in Marion 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: 265. 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