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What Does Radon Testing Involve?

Radon Testing Devices

Whether it’s through floor cracks, construction joints, wall cavities, service pipes, or even the water supply, radon has a lot of ways to invade your home. If you’re thinking of testing your property for radon, you want to know what such a test involves. How does the process of radon testing work?

Radon testing involves using devices like electret ion detectors, alpha track detectors, charcoal liquid scintillation devices, and continuous radon monitors to determine the levels of radon in your home. You may hire a professional to administer a radon test or even do so yourself.

If you still have questions about radon and testing for it, then you’re definitely going to want to keep reading. Ahead, you’ll learn more about the dangers of radon, why it’s tested, when you need to test, and what the results can tell you.

What Is Radon Testing?

First, let’s begin by discussing radon testing. What is it and why is it so necessary? Radon testing can detect the radioactive chemical element known as radon. Without this test, radon can easily go unobserved, as it has no taste, smell, or color.

As mentioned in the intro, radon can enter your home from a variety of sources. explains that as uranium in the soil begins to break down, radon results, often in gas form. Any openings within your home can then release the gas inside. These include everything from flooring and wall cracks to construction joints, service pipe gaps, suspended floor openings, and wall cavities.

Even if your home was sealed up tighter than Fort Knox, sometimes the materials used in home construction release radon. The CDC lists granite, gypsum, natural stone, brick, concrete, and sandstone have thorium, uranium, and radium, all radioactive elements.

Further, radon can enter through your local water supply. If you don’t use granular activated carbon filters for your water, then you could ingest radon daily without even realizing it.

Some parts of the United States are more at risk for radon exposure than others. The Environmental Protection Agency or EPA has a countrywide radon map that breaks down radon levels on a state by state basis.

The red states represent Zone 1. In these states, radon levels are above 4 picocuries per liter or pCi/L, which the EPA says is the max allowable radon limit for safety and health. States in Zone 2, which are colored orange, have between 2 and 4 pCi/L of radon, which is a safer range. The safest states are in Zone 3, which is yellow. These states have 2 pCi/L of radon or under.

According to the EPA, radon exposure could cause lung cancer if said exposure happens over many years. This cancer risk is present even in non-smokers, and the risk increases among those who already smoke.

To get the most accurate reading of radon levels on your property, the professionals administering the testing will do so multiple times. Radon levels can change by season and even from one day to another.

What Does Radon Testing Involve?

Should you decide to hire professional radon testers, they will use one or more devices for assessing the current levels of radon in the soil, air, and/or water. Here is an overview of those devices and how each one works, as outlined by the EPA.

Electret Ion Detectors

An electret ion detector is a lab-produced device with a Teflon disc inside. further explains that the disc undergoes charging via static electricity. Radon decay, which is ionic, will instantly be attracted to the Teflon disc. Each time radon sticks to the disc, the Teflon’s electric charge drops more and more.

The professional administering the test will take the Teflon disc out after testing and compare the disc’s original charge to its current charge to determine the levels of radon. 

Alpha Track Detectors

Another device for testing radon is an alpha track detector. Unlike an electret ion detector, you can buy an alpha track detector online or at some hardware stores. This detector features a layer of film, often made of plastic, that catches alpha particles. Each time the alpha particles make contact with the plastic, they etch a mark into the film.

After the test wraps up, the results can be processed in a lab using a chemical treatment to make each etching visible. Many tracks across the plastic film are indicative of the level of radon in your home.

Charcoal Liquid Scintillation Device

A charcoal liquid scintillation device, also referred to as a charcoal canister, includes a charcoal filter that absorbs the radon. Then, when the device goes to the lab, a liquid scintillation medium will detect how much radon is present or a sodium iodide counter will.

Continuous Radon Monitor

The above three examples are all passive radon testing devices, whereas a continuous radon monitor is considered active. The monitor itself can detect changing levels of radon or it may work with the above devices to augment their radon tracking abilities.

How Do You Know When You Need Radon Testing?

Now that you know what radon testing involves, you may wonder if it’s time to get your home tested for radon. The following scenarios are all good ones to schedule a radon test.

You’ve Never Tested Your Home

If you’ve lived in your home for years or even decades but have yet to test it for radon, now is as good a time as any to do the test immediately. You can’t know whether radon has been leaching into your water supply or through gaps through your home unless you test it. You can also determine if the building materials themselves are the source of radon with a test, so don’t wait.

You’re Selling Your Home

If your home will soon go on the market, testing for radon is one of the first things you should do. The EPA, in its Home Buyer’s and Seller’s Guide to Radon, recommends testing on a low level in your home even if you don’t use that level yourself. The EPA also suggests testing before putting your home on the market, not afterward.

Having radon test results to give to the homebuyer provides them peace of mind that they’re purchasing a safe and healthy home.

You’re Buying a New Home

If you’re the one who’s moving, a radon test comes highly recommended. Even if the home seller did a test of their own, homeowners may request their own testing for several reasons, note the EPA report.

One of these reasons is that the seller didn’t test at a low enough level of the home, such as the basement. The home might have been renovated since the last test, which would require a new radon test. Also, if a test is older than two years, the home should be retested, as the old results may not be accurate.

The homebuyer or even the home inspector can take care of radon testing. It’s not wise to proceed with signing final paperwork until the test results come back.

What Should You Do After a Radon Test?

What if the radon test results come back higher than you anticipated? You’ll need radon mitigation to make the home habitable. Depending on the source of the radon, mitigation measures can vary.

On your own, you can buy plastic sheeting to go beneath the slabs of your property to prevent radon from getting in through the soil. A vent pipe and fan system, also known as a soil suction radon reduction system, is another option. This system includes a series of pipes up to four inches that prevent radon from getting in. More simply, you can caulk and seal any openings and gaps.

If those at-home measures don’t work, you’ll need the assistance of radon mitigation specialists. They can depressurize the soil using an exterior or interior installation similar to a soil suction radon reduction system. An exterior active soil depressurization system has a fan attached to a vent. The fan is on the ground level of your home and sends air and radon through pipes and to the roof’s exhaust system.

An interior active soil depressurization system starts at the garage or basement and runs to the attic, including through each closet in your home. The fan in this system still sends the air and radon through the roof pipes.


Radon is a radioactive gas with no color, smell, or taste. It may also be a carcinogen. The only way to know how much radon you might have in your home is through radon testing. If you’ve yet to get a radon test for your property, don’t wait another day! This test can save lives.