Understanding radon test results

Radon is a natural radioactive gas that comes from the breakdown of uranium in soil and rock. You can’t see radon, smell it, or taste it, but it can build up in homes—especially in basements and ground-level rooms. Radon is important to take seriously because breathing high levels over time can increase the risk of lung cancer. The good news is that testing is simple, and if levels are high, radon can usually be reduced.

What your radon number means

Radon test results are usually reported in pCi/L, which stands for picocuries per liter of air. The higher the number, the more radon is in the air you breathe.

In the U.S., the Environmental Protection Agency (EPA) uses 4.0 pCi/L as an “action level.” That doesn’t mean 3.9 is “safe” and 4.1 is “dangerous.” It means that radon risk increases as numbers rise, and 4.0 is the point where fixing the problem is strongly recommended.

Here’s a helpful way to think about results:

• Below 2.0 pCi/L: Radon is generally considered low. Many people still choose to retest every few years or after home changes.
• 2.0 to 3.9 pCi/L: Moderate level. It may be worth retesting or considering improvements, especially if you spend lots of time in the lowest level of your home.
• 4.0 pCi/L or higher: Take action. A mitigation system is usually recommended.

Short-term vs. long-term tests

Radon levels change day to day due to weather, ventilation, and how a home is used. That’s why it matters what kind of test you took:

• Short-term tests usually run 2–7 days. They’re good for a quick check, but one short test can miss the “average” level.
• Long-term tests run 90 days to a year. They show a more accurate average and are often the best way to understand your real exposure.
• If your short-term test is 2.0 pCi/L or higher, many experts recommend following up with another test (often a long-term test) or moving forward with mitigation depending on your situation.

What to do if your radon is high

If your radon level is high, don’t panic. Radon problems are common, and proven solutions exist. The most common fix is a radon mitigation system, which usually uses a fan and pipe to pull radon from under the home and vent it safely outside. After installation, a follow-up test is important to confirm the level dropped.

If you have questions about your results or what steps to take next, consider contacting Utah Radon Services to talk through radon in your home, retesting options, and mitigation solutions.