Radon is easy to ignore because you cannot see, smell, or taste it. Yet this naturally occurring radioactive gas can enter a home through cracks and openings where the building meets the ground. The U.S. Environmental Protection Agency says testing is the only way to know a home’s radon level, and recommends testing every home regardless of age, foundation type, or location.
Why radon testing belongs on your home checklist
Radon forms when uranium in soil and rock breaks down. Outdoors it usually disperses, but indoors it can accumulate. Long-term exposure increases lung cancer risk, and the risk is higher for people who smoke. A neighbor’s result cannot predict yours because soil conditions, construction details, ventilation, and entry routes can differ from one house to the next.
Testing is useful whether you own or rent, and it matters in new construction as well as older houses. Radon-resistant building features reduce risk, but EPA still recommends testing after occupancy. If you are buying or selling, plan the test early enough to review the result and discuss mitigation without rushing the transaction.
Choose the right type of test
Short-term tests usually remain in place for a few days to 90 days, depending on the device. They provide a relatively quick snapshot and are practical for an initial check. Long-term tests remain in place for more than 90 days and give a better picture of the home’s year-round average because radon levels change with weather and household conditions.
You can buy a do-it-yourself kit from many hardware stores or qualified providers, or hire a credentialed radon professional. Follow the device instructions exactly. A test that is moved, opened early, placed incorrectly, or mailed late may produce a result you cannot rely on.
Pick the correct testing location
Place the device in the lowest level that is regularly occupied or could be used as living space without major renovation. In many homes that means a finished basement or a first-floor room. Choose a location where it will not be disturbed, away from drafts, direct sunlight, exterior walls, doors, windows, fans, fireplaces, and areas with high humidity such as bathrooms or laundry rooms.
Keep the device at the height and distance specified by its manufacturer. Do not put it directly on the floor or next to a wall unless the instructions say to do so. If your home is large, has separate foundation sections, or has an unusual layout, ask your state radon program or a qualified professional whether more than one device is appropriate.
Prepare the home for a short-term test
For tests lasting fewer than four days, EPA guidance generally calls for closed-house conditions beginning at least 12 hours before testing and continuing during the test. Keep windows and exterior doors closed except for normal entry and exit. You may operate heating and cooling systems that recirculate indoor air, but avoid fans or equipment that bring in outdoor air unless they are part of normal operation.
Do not start a short-term test during unusually severe storms or periods of sustained high wind. These conditions can affect the pressure differences that move soil gas into the home. Record the start time, test location, and any unusual event so you can interpret the result properly.
Complete and submit the test correctly
- Write down the device serial number and follow the activation instructions.
- Place it in the selected location for the exact required duration.
- Keep closed-house conditions when the instructions require them.
- Stop the test at the stated time, seal it immediately, and complete the information form.
- Send it to the laboratory promptly using the supplied packaging.
Some electronic monitors display an estimate directly, while passive kits must be analyzed by a laboratory. Keep a copy or photo of the result with your home records. A simple home inventory is also a useful place to record environmental tests, appliance information, and major repairs.
Understand the number on your result
In the United States, radon in air is commonly reported in picocuries per liter, abbreviated pCi/L. EPA recommends fixing a home when the result is 4 pCi/L or higher. Because no radon exposure is considered completely risk-free, EPA also advises homeowners to consider mitigation when results are between 2 and 4 pCi/L.
A single short-term result near or above the action level may need confirmation, depending on the level and the circumstances. Follow the instructions that accompany the result or consult your state radon program. When a result is very high, do not delay professional guidance while waiting for repeated tests.
What to do when radon is elevated
Radon problems can be fixed. A qualified mitigation contractor can evaluate the foundation and recommend a system, often using a vent pipe and fan to draw radon from beneath the building and discharge it safely outdoors. Ask for credentials, references, a written proposal, system details, warranties, and a post-installation test.
Do not treat an air purifier as a substitute for radon mitigation. Radon is a gas entering from the ground, so the solution normally focuses on controlling that entry pathway. If you are comparing indoor-air devices for particles, use a separate guide such as DaiLova’s air purifier buying guide.
Retest at sensible times
Retest after a mitigation system is installed to confirm it works, and maintain the system according to the contractor’s instructions. Consider retesting after major renovations, foundation work, HVAC changes, or a change in how the lowest level is used. EPA also notes that a buyer may request a new test when an older result is no longer recent, commonly when it is more than two years old.
A simple plan for this week
Start by visiting your state radon program or EPA’s provider page, choose a qualified kit or professional, and identify the lowest livable level in your home. Put the test dates on your calendar, follow the directions without improvising, and save the report. One small test replaces guesswork with a number you can act on.
