Radon is a gas you can't see, smell, or taste. It naturally comes from the breakdown of uranium in soil and rocks. Radon can enter your home through small cracks in floors, walls, or around pipes.
Breathing high levels of radon over time can increase your risk of lung cancer. Radon is the second leading cause of lung cancer in the U.S., and the number one cause among non-smokers.
Radon levels can vary by location. In Idaho, about 2 out of every 5 homes tested have radon levels higher than the Environmental Protection Agency’s (EPA) guideline of 4.0 pCi/L (picocuries per liter).
Radon information
When you breathe in radon gas, it can break down into tiny radioactive particles. These particles can get stuck in your lungs. Over time, they release small bursts of energy that can damage lung tissue. This damage can increase your risk of developing lung cancer.
Radon is the leading cause of lung cancer in people who don’t smoke. The Environmental Protection Agency (EPA) estimates that radon is responsible for about 21,000 lung cancer deaths each year in the United States.
Your Risk Depends on Several Factors
- How much radon you are exposed to
- How long you are exposed to it
- Whether you smoke or used to smoke
- Your overall health and other environmental or genetic factors
Utah woman warns others about radon after cancer diagnosis video
Improve your health by quitting smoking and fixing your home if radon levels are above 4 pCi/L.
See the chart below to understand how radon levels can affect your health.
Understand how radon levels can affect your health
| Radon Level (pCi/L) | If 1,000 smokers were exposed to this level of radon over a lifetime, about this many people could get lung cancer* | If 1,000 non-smokers were exposed to this level of radon over a lifetime, about this many people could get lung cancer* |
| 0.4 | 3 | -- |
| 1.3 | 20 | 2 |
| 2.0 | 32 | 4 |
| 4.0 | 62 | 7 |
| 8.0 | 120 | 15 |
| 10 | 150 | 18 |
| 20 | 260 | 36 |
Note: if you are a former smoker, your risk may be lower.
*Lifetime risks of lung cancer deaths from EPA Assessment of Risks from Radon in Homes (EPA 402-R-03-003)
Testing is simple and low-cost. Test the lowest level of your home where people spend time.
Types of Tests:
- Short-term test (3–7 days): Best done in winter.
- Long-term test (up to 1 year): Gives a better average of yearly radon levels.
Where to Get a Test Kit:
- Order a discounted kit at Air Chek.
- Pick one up at a hardware or home improvement store.
- Call 1-800-445-8647 for a free test (for Idaho residents).
You can also hire a certified radon professional through:
What Your Test Results Mean
Radon levels are measured in picocuries per liter of air (pCi/L). This tells you how much radon is in the air you breathe.
The Environmental Protection Agency (EPA) recommends taking action if your home's radon level is 4.0 pCi/L or higher. This usually means installing a radon mitigation system to lower the levels.
Even at lower levels, radon can still be harmful. The EPA also suggests that people consider fixing their homes if radon levels are between 2.0 and 4.0 pCi/L, especially if anyone in the home is at higher risk.
To be sure about your radon level:
- Test again to confirm your results.
- Use a long-term test to get a better idea of your average radon level over time.
Test levels and actions to take
| Radon Level (pCi/L) | Actions to Take |
| 0.4-1.3 | This is an average indoor radon level. Keep in mind that radon levels can change over time, so test again every 2 years. |
| 2.0-3.9 | Consider running a long-term radon test. Consider fixing your home. |
| 4.0 and higher | Fix your home! You may choose to do this yourself or hire a radon mitigation professional |
You can reduce radon levels by installing a mitigation system.
- DIY systems can cost $300–$600 in parts. there are many instructional videos on YouTube that can guide you through the process.
- Professional installation typically costs $1,500–$3,500.
- Building a new home? Radon-resistant features cost $300–$500 and are easiest to install during construction.
Find a professional at:
Building Codes for Radon Control
When installing a radon mitigation system, it's a good idea to follow the International Residential Code – Appendix F. This section of the building code provides guidelines on how to reduce radon levels in new and existing homes.
Important Note:
These radon control methods are not required by law in Idaho unless a city or county has specifically adopted them into their local building codes.
You may qualify for financial assistance if you're a limited income homeowner.
Programs that may help:
- HUD Community Block Grants 202-708-3587
- HUD "203K" Rehab Loans 202-708-2121
- EPA Environmental Justice Grants 800-962-6215
- USDA Home Repair Loans and Grants
Buying a Home:
Ask for a radon test during the home inspection. If levels are high, negotiate to have a mitigation system installed.
Building a Home:
Talk to your builder about radon-resistant construction techniques.
Renting a Home:
Landlords aren’t required to test for or fix radon issues, but you can test the space yourself and discuss the results with them.
Are you teaching others about radon? There are many free and easy-to-use materials to help. These include lesson plans, presentations, vocabulary flashcards, hands-on science activities, and websites made just for students and educators. The resources are great for classrooms, community events, and health fairs. They explain what radon is, why it’s a health risk, and how people can stay safe. All materials are designed to be clear, accurate, and easy to understand.