28%tests ≥ 4 pCi/L
3,933tests on record
1.5median pCi/L
Zone 1EPA zone (1993 prediction)

Test results in Frederick County

ResultShareEPA guidance
Below 2 pCi/L56%Below EPA's levels
2 to 4 pCi/L15%Consider fixing
4 pCi/L or more28%EPA recommends fixing

What the data shows

Where Frederick County sits among Maryland's 24 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%

How Frederick County compares

Frederick County ranks 4 of 6 among its neighboursShare of tests at or above 4 pCi/L · Radon test results from laboratories, 2008–2017 · whisker: 95% range
Washington County56%Carroll County42%Howard County31%Frederick County28%Loudoun County, Virginia27%Montgomery County18%Maryland 24%
Data table
AreaTests ≥ 4 pCi/LTests
Washington County56%1,259
Carroll County42%3,334
Howard County31%4,549
Frederick County28%3,933
Loudoun County, Virginia27%4,457
Montgomery County18%10,969
Maryland (24 counties)24%47,941

Same source as Frederick County. Other bordering counties: Adams County, Pennsylvania, Franklin County, Pennsylvania.

What it means for your home

About 1 in 4 results in Frederick 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: 3,933. 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