Check Radon Levels by Zip Code

The EPA does not publish radon data for individual zip codes. Instead, it classifies every county in the United States into one of three radon zones based on indoor radon measurements, geology, aerial radioactivity, soil characteristics, and foundation types. When you enter a zip code above, the tool identifies the county that zip code belongs to and shows you that county's EPA zone along with state-level radon data.

The three zones describe predicted average indoor radon levels. Zone 1 counties are predicted to average above 4 pCi/L, which is the EPA action level. Zone 2 counties are predicted to average between 2 and 4 pCi/L. Zone 3 counties are predicted to average below 2 pCi/L. A higher zone means the underlying geology in your area, often granite bedrock or uranium-bearing soils, tends to release more radon gas into the soil beneath homes.

Zip code and county risk data is a starting point, not a verdict. Radon enters a home through the specific path between the soil and the foundation, so the level in your house depends on your slab or basement construction, cracks and openings, and how air pressure moves through the building. Two neighboring homes can test at very different levels. That is why the EPA recommends testing every home, in every zone, regardless of what the map says. A short-term test kit or a professional measurement is the only way to know the number that actually matters: the radon concentration in the air your family breathes.

In Georgia, radon risk follows the geology. North Georgia counties along and above the Piedmont, including much of metro Atlanta, sit over granite and gneiss formations that produce more radon, and many of these counties are classified Zone 1 or Zone 2. South Georgia's coastal plain generally falls in Zone 3. If your zip code lands in a North Georgia county, testing is especially worthwhile. You can read more in our Georgia radon levels by zip code guide or see the full Georgia radon map by county.