How Radon Enters Your Home: A Simple Breakdown

(and How Often You Should Test)

When people hear about radon, one of the first questions they ask is:“How does it even get into my home?” The answer is simpler than you might think—but also more surprising. Radon doesn’t care how old your house is, what style it is, or whether it has a basement. Any home can have elevated radon levels.

Let’s break down how radon gets inside and how often you should test to keep your family safe.

What Is Radon?

Radon is a naturally occurring radioactive gas created as uranium in the soil breaks down. It’s invisible, odorless, and completely undetectable without testing.

Because it can build up indoors—especially in lower levels of the home—radon is the second leading cause of lung cancer in the U.S.The good news? It’s easy to test for and straightforward to fix.

How Radon Enters Your Home

Radon enters your home from the soil beneath it. Think of your house as a living, breathing structure. As it warms up, it naturally pulls air upward—kind of like a vacuum effect. This process is called the stack effect, and it can draw radon from the ground into your living space.

Here are the most common entry points:

1. Cracks in the Foundation

Even tiny cracks can allow radon to seep in. Concrete is porous, and radon can pass through hairline fractures just as easily as larger gaps.

2. Gaps Around Pipes and Plumbing

Openings around sump pumps, plumbing penetrations, and utility lines are frequent radon entry paths.

3. Crawlspaces

Homes with dirt-floor crawlspaces can experience higher radon levels, since exposed soil makes it easy for radon to migrate indoors.

4. Basements and Slab Floors

Slab-on-grade homes, basements, and daylight basements all sit directly on the soil, making them natural collection points for radon.

5. Construction Joints

Where floors meet walls—or anywhere different building materials join together—small gaps can form that radon can slip through.

6. Well Water (Less Common)

In some homes, radon can enter through well water. This is less common but still possible in certain geologic areas.

Bottom line: Radon gets in anywhere air gets in. Even a brand-new, airtight home can have elevated levels.

How Often Should You Test Your Home for Radon?

Testing is the only way to know your radon level, and it should be done regularly—not just once.

You should test your home:

Every 2 years

Radon levels can change due to weather, home aging, soil conditions, or construction nearby.

After major renovations

Adding insulation, finishing a basement, or installing energy-efficient windows can affect air flow and increase radon.

After installing a mitigation system

A follow-up test ensures the system is working and keeps radon levels consistently low.

During a real estate transaction

Buyers and sellers often require radon testing as part of the home inspection process.

If you’ve never tested before

Even if you’ve lived in your home for years, it’s never too late to start.

Why Regular Testing Matters

Radon isn’t a problem that stays the same over time. Levels can shift due to:

• Seasonal changes

• Soil moisture

• HVAC upgrades

• Foundation settling

• Weather patterns

• New landscaping or construction nearby
  

Routine testing keeps your home—and your family—safe. Most people are relieved to learn that if high radon is found, mitigation systems are highly effective and often affordable.