Radon Gas: What is It? Is It Dangerous? And How to Test For It

Mariel Loveland
Written by Mariel Loveland
Updated November 22, 2021
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  • Radon is a naturally occurring radioactive gas

  • Radon is the second leading cause of lung cancer

  • Most radon exposure happens in homes and workplaces

  • You can self-test for radon or hire a professional

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Out of sight, out of mind, right? Much like a forgotten family photo album, radon gas hangs out in basements and crawl spaces and can seep into your living space. You can’t see it, you can’t smell it, and you can’t taste it. Is it really that big of a deal? Yes, but don’t worry, testing and radon reduction strategies can help protect your family from exposure.

What is Radon?

Radon is a radioactive gas that you probably encounter every day—albeit in harmless amounts. This type of gas naturally occurs when uranium breaks down in soil, rocks, and groundwater. Radon only becomes a problem when it gets trapped indoors and can’t dissipate in the atmosphere.

Many homes are built on soil that contains natural uranium deposits. The Environmental Protection Agency (EPA) created a handy map of the country’s radon zones for reference. Radon is a sneaky gas because it can enter a building through any sort of crack, gap, drain, cavity, or construction joint. Basements and crawl spaces tend to collect the highest levels because they’re closest to the ground, but it can be found everywhere, including in your drinking water.

The Health Risks of Radon Exposure

Radon exposure doesn’t make you sick overnight. You can breathe in radioactive radon particles for years before there’s ever a problem, but it’s still the second leading cause of lung cancer in the United States. The EPA estimates that radon gas is responsible for 21,000 lung cancer deaths every year. People who smoke are 25 times more at risk from radon exposure, but you’re also at risk if you:

  • live in an area with high levels of radon.

  • spend a lot of time indoors.

  • spend a lot of time in rooms that are in contact with the ground.

  • have a job where you’re exposed to radon (like coal miners).

How to Test Your Home for Radon

Since you can’t see or smell radon gas, testing is the best way to find out whether your home contains dangerous radon levels. You can either hire a professional radon tester or use a DIY radon gas test kit, which is sold at most hardware stores for under $30. You’ll typically have to leave the kit out for three to seven days, and then mail it to a lab to get your results.

A DIY testing kit is a great first step, but it’s not as accurate as professional testing. Professionals have specialized equipment, training, and radon testing certification. They know where to test and how to test, but it will cost you. The average professional radon test costs $424 according to HomeAdvisor, but it’s a small price to pay for peace of mind.

What Should I Do If I Find Radon in My Home?

If you found radon in your home, don’t panic. Even high levels of radon can be successfully reduced. The EPA recommends bringing in a radon mitigation professional if levels are at or above four picocuries per liter—though lower levels still pose a health risk. Common radon mitigation strategies that professional will use to combat radon include:

Installing a Radon Reduction System

A well-placed radon reduction system can reduce radon levels in your home by as much as 99%. These systems typically use a fan or a pump to create ventilation and move radon particles away from your home. Even those that passively create ventilation can still cut your existing radon level in half. Most radon reduction systems cost between $450 and $1,500 to install. 

Sealing Your Home

Sealing unfinished basements, crawl spaces, floors, and walls will help prevent radon from entering your home. It costs an average of $4,600 to seal an entire basement, but even just filling in the cracks with a radon sealant can help. 

Crawl Space Encapsulation

A home’s crawl space is like an open front door for radon particles. It doesn’t take much for radon to rise from the open soil into your home. Encapsulating your crawl space using a radon membrane can help. According to HomeAdvisor, this process can cost between $1,500 to $15,000, depending on the size of the crawl space.

Radon Resistant Construction

If you’re building a new house, ask your contractor about radon-resistant construction. It’s cheaper to build these features in than adding them after the fact, largely due to the additional labor. These features include:

  • Adding a 4-inch layer of gravel beneath your foundation

  • Putting plastic sheeting or a vapor retarder above the gravel

  • Installing a vent in the gravel that rises to the top of your home

  • Encapsulating the crawl space

What If There’s Radon in My Water?

Sometimes radon is found in water, though the main health risk is inhalation. You can test your water using an EPA-approved test kit. If you find radon, you can reduce the levels by:

  • Installing an aeration system: Aeration systems are 95% to 99% effective and cost between $4,000 to $5,000. They work by moving water into a tank and injecting it with air to separate out the radon. Then, the radon is vented out of the tank and way from your home

  • Installing a charcoal scrubbing system: Charcoal scrubbing systems (also known as granulated activated carbon filtration systems) are 75% effective and cost between $500 and $1,500. They work similar to a charcoal filter. Carbon absorbs the radon, removing it from the water.

How to Find a Qualified Radon Mitigation Professional

The first step to ridding your home of radon is finding a qualified radon mitigation professional. Although there isn’t a federal licensing board for radon mitigation, some states require contractors to be licensed or registered. Additionally, your contractor may have a certificate from:

  • The National Radon Proficiency Program (NRPP)

  • American Association of Radon Scientists and Technologists (AARST)

  • The National Radon Safety Board (NRSB)

The truth is that radon mitigation strategies do work, and most of the time, they don’t cost much more than the average home repair. Whatever strategy you choose, always test your home after the work is done to ensure success. 

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