You can’t see it, smell it, or taste it, yet it could be present in the air you breathe every day. Radon is a naturally occurring radioactive gas that results from the breakdown of uranium in soil, rock, and water. It seeps up from the ground and can enter your home through cracks in the foundation, gaps around pipes, or other openings. Because it’s invisible and odorless, the only way to know if it’s in your home is to test for it. This leads many homeowners to ask a critical question: what is a safe radon level in a home?
The concern with radon isn’t just its presence; it’s the health risk it poses. After smoking, radon is the second leading cause of lung cancer. When you inhale radon gas, its radioactive particles can get trapped in your lungs, damaging the cells that line them. Over many years, this damage can increase your risk of developing lung cancer, even if you don’t smoke. This makes understanding and managing radon levels one of the most important steps you can take for your family’s long-term health and safety.
What is a Safe Radon Level in a Home? The Official Guideline
In the United States, the primary agency for environmental protection, the Environmental Protection Agency (EPA), has established a clear action level for radon. The EPA and the U.S. Surgeon General recommend that homeowners take action to reduce radon levels if the concentration is 4.0 picocuries per liter (pCi/L) of air or higher. This is not a safe/unsafe dividing line, but rather a level at which the health risk is significant enough to warrant mitigation efforts.
It’s important to note that no level of radon is considered completely risk-free. The EPA also suggests that homeowners might want to consider taking action even at levels between 2.0 and 4.0 pCi/L. The goal is to get your radon levels as low as reasonably achievable. The World Health Organization (WHO) sets an even lower recommended reference level, advising action at 2.7 pCi/L. Think of it like this: the lower the radon level in your home, the lower the health risk to you and your family.
How to Know Your Home’s Radon Level
Since you can’t detect radon with your senses, testing is the only way to know your home’s specific level. The good news is that testing for radon is simple and inexpensive. There are two main types of tests available to homeowners.
Do-It-Yourself Test Kits: These are widely available at hardware stores, home centers, and online. You simply place the kit in the lowest lived-in level of your home (like a basement or first-floor den) for the period specified on the package, then mail it to a lab for analysis. These are a great, affordable starting point.
Professional Radon Testing: You can also hire a qualified radon tester. This is often done during real estate transactions. Professionals use continuous radon monitors that can provide more detailed data over a shorter period. Whichever method you choose, the key is to test. It’s the first and most crucial step in protecting your home.
What to Do If Your Radon Level is High
Receiving a test result at or above 4.0 pCi/L can be concerning, but it’s a problem with a proven solution. A high radon level does not mean you have to abandon your home. It means it’s time to install a radon mitigation system.
The most common and effective method is called active soil depressurization. A certified radon mitigation professional will install a vent pipe and fan system that pulls radon gas from beneath your home’s foundation and safely vents it outside, above the roofline, where it quickly dilutes to harmless concentrations. These systems are remarkably effective, often able to reduce radon levels by more than 50%, and in many cases, they can reduce them to below 2.0 pCi/L.
The cost of a system can vary, but it is a one-time investment that makes your home safer and is often comparable to other common home repairs. If you are building a new home, you can also ask your builder to include radon-resistant construction features, which are cost-effective to install during construction.
Maintaining a Low Radon Level in Your Home
After you’ve tested and, if necessary, mitigated your home, it’s wise to maintain an awareness of your radon levels. The EPA recommends testing your home at least every two years. You should also consider retesting in several situations: if you make any structural changes to your home, if you occupy a previously unused lower level (like finishing a basement), or after you have installed a mitigation system to ensure it is working correctly.
Simple habits can also help. While they are not a substitute for a mitigation system if your levels are high, increasing ventilation in your home, sealing major cracks and openings in your foundation, can help reduce the amount of radon entering your living space as part of an overall strategy.
In the end, the question of a safe radon level has a clear answer: the lower, the better. While 4.0 pCi/L is the official action level, aiming for the lowest level you can achieve is the best practice for your health. By testing your home, understanding the results, and taking action if needed, you can gain peace of mind and create a healthier indoor environment for everyone who lives with you.