What Does Radon Testing Detect In Your Home?

Radon testing detects the presence of radon gas in the air inside your home. It measures the concentration of this radioactive gas, typically reported in picocuries per liter (pCi/L) of air. The test tells you whether your family is being exposed to levels that warrant action to reduce the gas.

What Exactly Is Radon Gas?

Radon is a naturally occurring radioactive gas. It forms when uranium in soil, rock, and water breaks down. You cannot see it, smell it, or taste it.

The gas moves up through the ground and can enter buildings through cracks in foundations, gaps around pipes, and other openings. Once inside, it can build up to levels that are dangerous to breathe.

Radon decays into tiny radioactive particles. When you inhale these particles, they can damage the cells lining your lungs. Over many years, this damage increases the risk of lung cancer.

Radon is the second leading cause of lung cancer after smoking. For people who have never smoked, radon exposure is the leading cause of lung cancer.

What Does Radon Testing Detect In Your Home?

Radon testing measures the amount of radon gas in the air you breathe inside your home. The result is a number called a radon level, measured in picocuries per liter of air.

The Environmental Protection Agency (EPA) recommends taking action to fix your home if the radon level is 4 pCi/L or higher. The EPA also suggests considering action for levels between 2 and 4 pCi/L because no level of radon is completely safe.

A radon test does not detect other indoor air contaminants. It only measures radon gas concentration. The test does not tell you where the radon is coming from or how long it has been there. It gives you a snapshot of the current level in the area being tested.

Radon levels can vary from room to room and change over time. Weather, season, and how your home is ventilated all affect the readings. The lowest livable level of your home is the most important place to test.

How Do Radon Tests Work?

There are two main types of radon tests: short-term and long-term. Both types are reliable when used correctly.

Short-term tests stay in your home for 2 to 90 days. The most common types use charcoal canisters or liquid scintillation detectors. These tests give you a quick answer, which is useful when you are buying or selling a home.

Long-term tests stay in place for more than 90 days. They use alpha track detectors or electret ion chambers. Long-term tests give a better picture of your average year-round exposure because they capture seasonal changes in radon levels.

Continuous radon monitors are electronic devices that measure radon over time and display the results. These are often used by professional radon testers.

All radon test devices must be placed correctly to give accurate results. They should go in the lowest livable area of your home. The test must be placed at least 20 inches above the floor and away from drafts, heat sources, and high humidity.

Windows and doors must stay closed for at least 12 hours before and during a short-term test, except for normal entry and exit. This is called closed-house conditions and it ensures the test measures the air you actually breathe.

What Do Radon Test Results Mean?

Radon levels are measured in picocuries per liter of air. The average indoor radon level in the United States is about 1.3 pCi/L. The average outdoor level is about 0.4 pCi/L.

Here is how to understand your results:

• Below 2 pCi/L: Low level. No action is required, though no level is risk-free.
• 2 to 4 pCi/L: Moderate level. The EPA recommends considering a radon reduction system.
• 4 pCi/L or higher: High level. The EPA strongly recommends fixing your home. This is the action level.

These numbers are not arbitrary. The 4 pCi/L action level was set based on the technology available to reduce radon and the health risks at various exposure levels. It is not a safe threshold. It is a practical guideline for when to act.

Your risk of lung cancer from radon depends on two things: the radon level in your home and how long you are exposed to it. Higher levels and longer exposure both increase risk. Smoking combined with radon exposure creates a much higher risk than either factor alone.

Why Should You Test Your Home?

Radon is present in every state in the United States. Some areas have naturally higher radon levels than others, but local maps cannot tell you what your specific home contains. The only way to know is to test.

The EPA and the Surgeon General recommend testing all homes for radon. This includes homes with basements, homes on slabs, and homes with crawl spaces. New homes and old homes can both have radon problems.

Radon enters a home through any opening that touches the soil. Common entry points include:

• Cracks in concrete floors and walls
• Gaps in suspended floors
• Gaps around service pipes
• Construction joints
• Cavities inside walls
• Water supply systems

Homes that test high for radon can usually be fixed. A radon mitigation system, typically using a vent fan and pipe system, can reduce radon levels by up to 99 percent. These systems are called active soil depressurization systems.

The cost of fixing a radon problem varies. It depends on the size of your home and the type of foundation. Most systems are installed by licensed radon mitigation contractors.

How Often Should You Test?

Test your home for radon at least once if you have never tested it. After that, retesting every two years is a reasonable practice. The EPA does not specify a strict retesting interval, but periodic testing is wise because radon levels can change.

You should also test again if you make major changes to your home. Remodeling a basement, adding an addition, or installing a new heating or cooling system can change how radon enters and moves through your home.

If you buy a new home, ask whether it was built with radon-resistant features. These features include a layer of gravel under the foundation, a plastic sheeting barrier, and a vent pipe. Even with these features, you should test after moving in.

If you buy an existing home, make radon testing part of the home inspection. Many home inspectors offer radon testing as an optional service. Some states require radon testing or disclosure during real estate transactions.

What If Your Home Tests High?

If your initial short-term test shows a radon level of 4 pCi/L or higher, do not panic. A single high reading does not mean your family is in immediate danger. It means you should take the next step.

Run a second short-term test to confirm the first result. If you used a home test kit, consider hiring a professional to do a follow-up measurement. Professional testers use calibrated equipment and follow strict protocols.

If the confirmed level is still 4 pCi/L or higher, contact a qualified radon mitigation contractor. You can find certified professionals through state radon programs or the National Radon Proficiency Program.

Radon mitigation is a well-established process. The most common system uses a fan to pull radon from beneath the foundation and vent it outside through a pipe. This system is effective and relatively inexpensive compared to many other home repairs.

After mitigation is installed, test again to confirm the system is working. Most systems reduce radon levels to below 2 pCi/L. Retest every two years after that to make sure the system continues to function properly.

Can You Test For Radon In Water?

Radon can also enter your home through well water. When water containing radon is used for showering, washing dishes, or other household tasks, the gas is released into the air and you can breathe it in.

If your home uses a private well, the EPA recommends testing your water for radon. Homes supplied by public water systems are generally less of a concern because most public systems treat water to remove radon.

Water testing is separate from air testing. A standard radon air test does not measure radon in water. If you have a private well, you need a separate water test kit from a certified laboratory.

Radon in water is much less of a health risk than radon in air. The primary risk from water radon comes from breathing the gas released during household water use. The risk from drinking the water itself is considered very small.

If your water test shows high radon levels, treatment options exist. Aeration systems or granular activated carbon filters can remove radon from water. These systems are installed by licensed water treatment professionals.