With all you do to keep your home happy and healthy, you may be overlooking one key factor that’s harder to control: Your home’s radon levels.

Radon is a radioactive gas that occurs when certain elements in soil, rocks, and water break down, often just below your home. It is odorless and colorless, entering your home—especially your basement—through cracks and holes in the foundation. Breathing in radon can damage health over time, as it is the #1 cause of lung cancer in nonsmokers!

What Is a Safe Radon Level?

Measured by the ‘rate of decay’, expressed as pCi/L (or picocuries per liter), the EPA considers radon levels of 4 pCi/L or higher most hazardous—but any level can still pose a risk. In fact, did you know more than 30 states have elevated radon levels?

Depending on where you live, you can be subject to increased radon levels by zip code, but no matter the state you call home, radon testing should be part of any yearly home maintenance routine! Monitoring radon levels each year can help you stay ahead of possible issues in your home.

Radon Levels by Zip Code

Discover the top five states reporting the highest radon levels.

Zip Code 995: Alaska

Because rock, soil, and water can emit radon, Alaska’s glaciers, crisp waters, and fertile volcanic soil make it the perfect breeding ground for radon. While it is not heavily populated, it is still crucial for all residents to keep up on radon inspections, as the state’s radon levels by zip code can be upwards of 10.7 pCi/L.

Zip Codes 570–577: South Dakota

Nestled in the northern Midwest and known for being scattered with mountain ranges, South Dakota is not heavily populated but is geographically the perfect place for rock and soil decay. This terrain results in a high concentration of radon, with the state reporting radon levels as high as 9.6 pCi/L.

Zip Codes 150–196: Pennsylvania

While Pennsylvania doesn’t lead the nation in radon levels—reporting around 8.6 pCi/L—approximately 40% of homes in the state have radon levels above the EPA’s action guideline of 4 pCi/L.

Zip Codes 430–459: Ohio

Ohio is home to a geological formation called the Ohio Shale, which contributes large quantities of both uranium and radium to Ohio’s soil, which continuously break down and release radon gas. Typically, radon levels in the state fall around 7.8 pCi/L.

Zip Codes 980–994: Washington

Because elements in water and ice can break down and release radon gas, areas populated by glaciers and other ice formations can cause high radon levels upwards of 7.5 pCi/L. Washington is home to the most glaciers of any state in the continental U.S. and has over 1,000 dams, contributing to its high ranking.

Your Radon Level by Zip Code

How does your home state measure up? Click here to see other states in the nation rank, from highest to lowest radon levels. However, it’s important to note that some states may only appear to have lower radon levels due to insufficient testing data. That’s why it’s always a good idea to test for radon, regardless of where your state ranks.

Protect Your Home and Test for Radon

Radon is the #1 one cause of lung cancer in nonsmokers. The only way to know if you’re being exposed is to test.

SHOP TEST KITS about this specific item

What Is the State of Your Air?

Some states rank higher than others, but the fact is, no matter where you live, radon should be on your radar. While the EPA recommends annual testing if you don’t have an active radon system and every other year if your home has an active radon system, we always recommend testing once yearly to monitor radon levels.

Order an AprilAire Short-Term Radon Test Kit for fast, easy, and reliable radon testing, and connect with an AprilAire Healthy Air Professional in your area if you require mitigation.

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