Understanding Radon Gas: Risks, Testing, and Mitigation for Home Buyers

If you’re buying a home or already own one—especially in the Portland, Oregon metro area—there’s an invisible risk you need to know about: radon gas.

Whether you’re a first-time home buyer or an experienced homeowner, understanding radon is crucial for your safety and long-term health. It’s also a topic every good real estate agent in Portland should be ready to discuss. In this post, we’ll cover what radon is, why it matters, how to test for it, and what to do if it’s found in your home (or in the home you want to buy).

What Is Radon Gas and Why Should You Care?

Radon is a naturally occurring radioactive gas that forms underground as uranium in soil and rock breaks down. It’s odorless, colorless, and tasteless—which means you won’t know it’s there unless you test for it. Outdoors, radon disperses quickly and isn’t considered dangerous. However, when it enters your home—often through cracks in the foundation or gaps around pipes—it can accumulate to hazardous levels.

According to the Environmental Protection Agency (EPA), radon is the second leading cause of lung cancer in the United States, behind smoking. In areas like Portland, Oregon, radon is particularly concerning due to the region’s unique terrain and geology. Certain Portland neighborhoods show higher radon concentrations than others, and homes with basements or crawl spaces are at greater risk.

For home buyers and real estate agents in Portland, understanding radon should be a key part of the home inspection and negotiation process.

Testing for Radon in an Existing Home

If you’re a homeowner, testing your current home is one of the smartest things you can do for your health and peace of mind. Radon testing is easy and affordable, with at-home test kits ranging from $50–$150. These kits can be purchased online, at hardware stores, or sometimes even provided free through state programs like Oregon.gov’s radon awareness initiative.

There are two common types of radon tests:

• Charcoal Test Kits: These absorb radon over a few days and are mailed to a lab for analysis. They’re inexpensive and accurate but take time to process.

• Continuous Radon Monitors (CRMs): These digital devices take hourly readings over 48 hours and are often used in real estate transactions because they provide quicker results.

If your test comes back with radon levels at or above 4.0 picocuries per liter (pCi/L), the EPA recommends taking action to lower the levels in your home.

Radon Mitigation in a Home You Already Own

If elevated radon levels are detected, don’t panic—mitigation is possible and often very effective. Common radon mitigation strategies include:

• Sealing cracks and gaps in your basement floor, foundation, or crawl space

• Improving ventilation, especially in basements and lower-level rooms

• Soil depressurization systems, which are considered the most effective long-term solution

Soil depressurization systems involve placing a polyethylene sheet over the soil in crawl spaces or digging beneath basement floors. A fan system is then installed to pull radon from beneath the home and release it safely above the roofline.

Mitigation costs typically range from $1,500 to $2,200, depending on your home’s size and foundation. A certified radon mitigation contractor can assess your specific needs and recommend the right solution.

Testing for Radon When Buying a Home

If you’re buying a home in Portland, especially in an area known for higher radon levels, you should absolutely request a radon test as part of your home inspection.

Here’s how it typically works:

• Your real estate agent or inspector places a continuous radon monitor (CRM) in the lowest level of the home (like a basement) for 48 hours.

• The device measures and logs hourly radon levels during that time.

• Results are reviewed, and if levels exceed 4.0 pCi/L, you can negotiate repairs or radon mitigation with the seller before closing.

Although this CRM method is faster, it’s not as accurate as the longer-term charcoal test. But in a real estate transaction, time is limited—so the quicker test is standard.

Pro Tip: If you’re working with a Portland real estate agent, like one of our agents at Paris Group Realty, LLC, make sure they’re knowledgeable about local radon risks and experienced in negotiating mitigation costs into the purchase contract.

Radon-Resistant Construction for New Homes

If you’re building a new home in Portland or buying new construction, you have the advantage of preventative planning. Builders can incorporate radon-resistant features during construction, including:

• Installing a polyethylene vapor barrier over the soil in crawl spaces

• Running ventilation piping beneath the slab or foundation

• Using radon collection points with exterior fans to redirect gases safely outside

These systems are cost-effective during initial construction and can save you money on retrofitting later. If you’re a home buyer considering a newly built home, ask your builder or real estate agent whether radon-resistant techniques were used.

Why Regular Testing Matters

Radon levels can change over time. Factors like:

• Soil shifting or erosion

• Foundation cracks from settling

• Remodeling or home additions

• Seasonal weather patterns

…can all impact the amount of radon entering your home. That’s why the EPA recommends retesting your home every two to five years, or anytime you move, remodel, or notice structural changes to the property.

If you’re living in or buying a home in Portland, where radon levels are known to fluctuate, regular testing is part of responsible homeownership.

Radon and Real Estate: What Buyers and Sellers Should Know

For home buyers:
Make sure radon testing is included in your inspection process, especially in Portland neighborhoods known for elevated radon levels (your real estate agent can guide you here). If elevated levels are found, you can often negotiate that the seller covers mitigation before closing.

For home sellers:
Consider testing your home for radon before listing it. It shows transparency and may give buyers more confidence in the safety of the home. If high radon levels are found, addressing it early lets you control the timeline and cost of mitigation, rather than rushing during escrow.

For real estate agents:
It’s important to educate clients about radon in a calm and informed way. Buyers may be alarmed to hear the word “radioactive,” but with facts and a mitigation plan, it’s an issue that can be resolved quickly and affordably.

Conclusion: What You Need to Know About Radon as a Home Buyer

Radon may be invisible, but it doesn’t have to be an unknown. Whether you’re buying your first home, building a new one, or simply want to stay safe in your current property, testing for radon and taking mitigation steps if needed is a simple and worthwhile process.

In a city like Portland, Oregon, where terrain and geology can heighten radon risks, staying informed is especially important. Fortunately, the solutions are accessible—and so are the professionals who can help you implement them.

Need Help Navigating Radon Testing or Mitigation in Portland?

At Paris Group Realty, LLC, we help our clients make informed decisions at every step of the home buying or selling process—including radon awareness and safety. We’ll connect you with trusted inspectors, mitigation experts, and help you negotiate any needed improvements into your transaction.

📩 Have questions about radon, real estate, or buying a home in Portland? We’re here to help you make the safest, smartest move possible.
Reach out to our team today at info@parisgrouprealty.com or call (503) 926-5213.