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Radon in Washington County, Ohio

Washington County, Ohio, is in EPA radon Zone 2: predicted average indoor radon screening level from 2 to 4 pCi/L (moderate potential). Radon laboratories reported 290 building tests here for 2008 to 2017: median 3.1 pCi/L, with 38.1% at or above EPA's 4 pCi/L action level (Ohio 51.6%, US 36.5%).

Zone 2
EPA radon zone (1993 county map)
3.1
median lab test, pCi/L (2008-2017)
38.1%
of lab tests at or above 4 pCi/L
290
buildings tested by labs, 2008-2017

Radon test results in Washington County

Radon test results on file for Washington County, OH, with state and national comparison
Test resultsPeriodTestsTypical result4 pCi/L or more
Radon testing laboratories2008-2017290median 3.1 pCi/L38.1%
Ohio, all counties (labs)2008-201784,325n/a51.6%
United States (labs)2008-20171,408,802n/a36.5%

Test results describe buildings whose owners chose to test and whose results reached the lab or agency, not a random sample; small counts swing widely. State and US shares are computed from county counts and percents. The laboratory data comes from national radon testing laboratories and supplements EPA's zone map.

Radon in nearby counties

CountyEPA zoneLab tests4 pCi/L or more
Wood County, WVZone 254915.9%
Pleasants County, WVZone 21550%
Noble County, OHZone 23431%
Morgan County, OHZone 2930%
Monroe County, OHZone 24058.3%
Ritchie County, WVZone 2105.6%

The six counties with the nearest centers.

What to do about radon in Washington County

Test the building. EPA recommends fixing a home at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, and says there is no known safe level of exposure. Ohio's state radon program can point you to testers and test kits.

Buying here? The Environmental Records Report lists this county's radon zone and test results with the flood zone, mapped faults, power lines and federal contamination records near the address.

Check one Washington County address

Environmental Records Report, $29. PDF and JSON, usually ready in about a minute.

Radon in Washington County: questions

What is the radon level in Washington County?

The median of the 290 laboratory tests reported for Washington County (2008 to 2017) was 3.1 pCi/L, and 38.1% of them were at or above 4 pCi/L. These are results of tested buildings; a single home can be far above or below them.

Is Washington County in radon Zone 1?

No. EPA's 1993 map puts Washington County in Zone 2 (predicted average indoor radon screening level from 2 to 4 pCi/L (moderate potential)). EPA says homes in every zone can have high radon and should be tested.

How does radon in Washington County compare with Ohio?

38.1% of laboratory tests in Washington County were at or above 4 pCi/L for 2008 to 2017, against 51.6% across Ohio (84,325 tests) and 36.5% nationally. 53 of Ohio's 88 counties are in Zone 1.

Should I test for radon in Washington County?

Yes. EPA recommends testing every home whatever its zone: "This map should not be used to determine if individual homes need to be tested." Fix the home at 4 pCi/L or more and consider a fix between 2 and 4 pCi/L; EPA says there is no known safe level of radon exposure.

More for Washington County

Other free hazard lookups

All of these, plus wetlands, FEMA hazard ratings and the federal contamination lists, are in the Environmental Records Report for any US address ($29).

Radon in every Ohio county · Radon map of every state

Data compiled 2026-10-20. County FIPS 39167. County-level screening information, not a radon measurement of any building.