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Radon Testing: What It Is And Why It’s Important For Homeowner Safety

Cathie Ericson6-Minute Read
February 05, 2021

You might not have thought of radon since your high school chemistry class, but it’s actually a substance that could be lurking in your home – even if you don’t know it. That’s why radon testing is an important thing to know about and make sure has been taken care of in your home, or one you’re buying or selling.

What Is Radon?

According to the American Cancer Society, radon is caused by radon gas that’s in the air and breaks down into tiny radioactive elements (radon progeny) that can lodge in the lining of the lungs, where they can give off radiation, ultimately potentially damaging lung cells that can lead to lung cancer.

In fact behind smoking, it’s the second leading cause of lung cancer (although most radon-related lung cancers develop in those who already smoke). However, it still can be a threat to anyone, so you want to make sure you avoid having high levels of radon, which can impair the indoor air quality of your property and potentially harm your home’s residents.

Radon isn’t something you can see, unlike mold or other problems that can affect the health of your home. That’s why you’ll want to test for it. If your resulting test shows a radon level of 4 picocuries per liter (pCi/L), or higher, then you’ll want to make efforts to reduce it.

How Does Radon Enter A Home?

Radon is a naturally occurring gas that is caused by uranium breaking down in the soil. While it can happen anywhere, there are some regions in the United States that are more prone to it. Since radon is found in the soil, it can enter your home in many ways, none of which are a homeowners’ fault. In fact, it can be found in homes that are new or old, well-sealed or drafty, and with or without basements.

For example, it can come in through tiny pores or cracks in the foundation or gaps in the walls and floors, or can be found in your drinking water if you have a well. Since you can’t see, smell or taste radon, you won’t know it’s there until you test for it.

According to the Environmental Protection Agency (EPA), one of every 15 homes in the United States has elevated radon.

What Is Radon Testing?

Fortunately, it is relatively easy and affordable to test for radon.

With all of the various types of tests, you’ll be looking for the presence of radon and how much is there, as expressed by pCi/L as mentioned above. The goal is to have less than 2 pCi/L and not more than 4 pCi/L.

How To Test For Radon

There are two kinds of tests: those done professionally by an inspector, and those homeowners can do themselves by purchasing a simple kit at the hardware store. With a DIY test, you’ll position it at the lowest level of your house for at least 48 hours, then return the test to a lab for them to analyze.

For a professional test, consider contacting a radon professional certified by the National Radon Proficiency Program (NRPP)  or National Radon Safety Board (NRSB), which are two independent boards.

Short-Term Tests

With a short-term test, you can get your results in about 2 – 3 days, giving you a quick read on whether you have an issue that you might want to pursue with more vigilance.

These tests typically cost $15 – $300, according to Fixr, depending on whether a professional conducts it or you DIY. There are several types, all of which have average DIY costs that range from $15 – $35, with professional costs ranging from $150 for a charcoal canister up to $300 for the electret ion chamber.

Long-Term Tests

With a long-term test, your radon will be tested for more than 90 days and up to a year. That’s because radon levels can fluctuate, so longer-term tests can be more accurate given that they take into account a longer period of time. Often a professional will recommend you run a short-term test first and then a long-term one if high levels of radon are detected.

There are several types of long-term tests; which can run from $25 for an Alpha Track test – a simple sheet of plastic that shows etchings when radon is present, up to $300 for a continuous monitor test, which is more commonly done by professionals.

How Often Should You Test Your Home For Radon?

The EPA recommends having a radon inspection at least every two years and more often if you have done any renovations or additions. Also, if you intend to finish a basement that hasn’t been tested for radon, you want to make sure you test first, since you should always test at the lowest level where you will be living.

How To Reduce Radon Levels In Your Home

While it can be impossible to eradicate radon in some cases, there are steps a homeowner can take to eliminate high levels of radon.

Seal And Caulk Potential Access Points

Although radon can enter in many ways, it’s still better to keep soil from entering the house. That’s why it’s worth sealing and caulking areas where radon could potentially enter your home, such as cracks in the walls, floor and foundation – which can also help better insulate your home as a bonus. However, this is not a permanent solution for keeping radon out.

Ventilate Your Crawl Space

Since your crawl space is usually near the lowest part of your house, ventilating it and sealing it can help reduce the level of radon in your home.

Install A Radon Mitigation System

There are two main types of radon mitigation systems.

Active suction systems: These create negative air pressure. You cover the earth floor with a high-density plastic sheet, and add a vent pipe and fan that draws the radon from under the sheet and vents it outside.

Pressurization method: With this type of system, you keep radon out by blowing air continuously into the lowest level of your home. Note that for it to be effective, the doors at the lower level and all the windows must be kept closed and sealed.

Radon And Real Estate: FAQs

If you hadn’t thought about radon before, you might have a lot of questions as either a home buyer or home seller. Here are a few that frequently come up, along with advice on handing the issue. Note: It’s always best to work with a real estate agent to help you with these and other facets of buying and selling a home.

Is It Difficult To Sell A House Without A Radon Test?

Having a radon test can be a smart way to show that you’ve done all your due diligence in getting your house ready for the market. While it’s not required, any extra step you can take to prove the safety and health of your home will be appreciated when buyers come through. And if you find a problem, you’ll have time to take remediation action so the buyers can feel confident the house is move-in ready.

Should I Get A Radon Test When Buying A Home?

The short answer is yes; just to be sure, especially since, as mentioned, you need to test every 2 years for it to be accurate. And even if a neighbor’s house shows a clean radon test, that doesn’t mean you are automatically in the clear since radon levels can vary from house to house.

Does The Buyer Or Seller Pay For A Radon Test?

Either party can pay for the radon test. It’s smart for a seller to do the test before putting the house on the market, but if the radon test hasn’t been conducted, then the buyer should have one done. They can make it a condition of the inspection and ask the seller to pay for it. Of course, when you’re buying a home, almost anything is negotiable in terms of who pays for what, which is why it’s smart to have a real estate agent guiding you through the process.

Is It Safe To Buy A Home With High Radon Levels?

It’s not … as mentioned above, radon can cause lung cancer, so you’ll want to make sure any radon levels are addressed before moving in.

Do Sellers Need To Fix A Radon Problem?

Again, radon mitigation can be negotiable, most buyers will expect the homeowners to take care of the issue prior to moving in.

The Bottom Line

Buying a home can be a complicated process, but it’s important to pay attention to issues that might seem small, like radon testing, because they can be far more important that the color of the house’s kitchen. It’s wise to become informed prior to buying a home, so take the time to educate yourself by checking out more Homeowner Tips on the Rocket Homes® blog.

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Cathie Ericson

Cathie Ericson writes about personal finance, real estate, small business, education, retail/ecommerce and other topics for a host of brands and websites. Her work has been featured on major media websites, including U.S. News & World Report, Forbes, Business Insider, The Oregonian, Industry Dive, Boston Globe, CNBC,, and Yahoo Finance, among many others. Find her