Vintage homes have all kinds of charm. They have strong bones, a solid construction, built-in shelving, and unique architectural details. Some may even come with years of history attached. Still, they may have issues like mold and radon leaks. 

But does that mean you won’t find radon in new homes? Let’s find out. 

Are New Homes Radon-Resistant?

For the most part, yes. In the late 1900s, radon-resistant construction started to become more popular in the country. Older homes had no such protection. So now, people don’t worry as much about radon in new homes. 

The numbers also reveal an encouraging trend:

• As per the EPA, one estimate from a survey by the National Association of Home Builders (NAHB) found that since 1990, over 1.5 million homes have been built with radon-resistance features.
• Another survey by the Home Innovation Research Labs pegs this number at 3 million homes, also as per the EPA.
  

What are Radon-Resistant Features in New Homes?

Radon-resistant features in new homes are conscious design choices that prevent radon from seeping into a building. When implemented well, they can greatly reduce radon exposure risks for residents. 

These features include many elements that help keep radon out of the house. Here’s what new homes now use:

• A Gas-Permeable Layer: A thick sheet of coarse gravel placed under the foundation, so radon can move freely beneath the house instead of seeping into it
• Plastic Sheeting: Heavy-duty sheeting placed above the layer of gravel as a barrier that prevents radon from entering the house
• A Depressurization Pipe: A pipe that runs from under the foundation all the way up through the roof, so radon has a clear way out instead of building up indoors
• Sealed Foundation Cracks: Caulking and sealing of all the gaps in the slab, walls, and around pipes to cut off common entry points for radon in new homes
• A Junction Box: A pre-installed outlet in the attic, so a vent fan can be added in later to push the gas out if testing shows high radon levels
  

Still, while modern homes are mostly radon-resistant, they’re not entirely radon-proof. Let’s find out why.

8 Reasons Your New Home May Not Be Radon-Free

Your new home may still be vulnerable to radon exposure because of the following reasons:

1. Radon-Heavy Land or Soil 

Radon is formed when uranium and radium in the soil break down. Some regions in the US have naturally higher concentrations of these metals. And if your home sits on that kind of land, the risk of radon exposure goes up significantly. 

The EPA has mapped out the radon zones across the country. Homes in Zone 1 areas face the highest risk. But even Zone 2 and Zone 3 aren't entirely safe because radon has been found in all states in the US. 

The only sure way to know if your house is safe? Radon testing. 

In case you’re worried about radon exposure, get in touch with InHaus Lab and book an appointment for radon testing today. 

2. No Federal Mandate for Radon-Resistant Construction

There’s no federal law that requires builders to include features to keep out radon gas in new constructions. It’s largely left to each state and local jurisdiction, and many areas don’t enforce it by law.

This means two homes built in the same year, in the same city, can be completely different in terms of radon protection. It all depends on: 

• The local laws
• The buyer you chose
• The features they included
  

3. Improperly Installed Radon Mitigation Systems 

Radon-resistant features only work when they’re correctly installed. A pipe placed in the wrong spot, a gap in the plastic sheeting, or a poorly sealed joint can all undermine the entire system. If that’s the case, there’s a clear pathway for radon in new homes.

This Reddit post discusses one such instance, where, despite having a pipe and a fan installed in a new home, radon levels continued to rise.

4. Foundation Cracks or Gaps

New homes settle over the years. As they do, small cracks can form in the foundation, around the pipes, and along wall joints. Through these small gaps, radon can find a way in. All it needs is the tiniest opening. 

This may even happen within months of a new construction. The only way to know is to measure the levels of the gas. There are no physical tells. That’s why the importance of radon testing cannot be overstated.

5. Pressure Differentials That Draw Radon In

The air inside your home is usually at a lower pressure than the soil below it. This pressure difference acts like a suction force and pulls gases from the soil up through any cracks.

Among those gases, radon may also be present. 

This happens in almost every home to some degree. The tighter and more energy-efficient the build, the more pronounced the effect can be, since there's less natural airflow to balance things out.

6. Radon Emissions from Building Materials 

Some building materials also release radon in small amounts. Common examples of such materials include concrete, some types of bricks and natural stones, especially granite. 

Generally, these are not major sources of radon in new homes. But in a tightly built house with limited ventilation, even low-level emissions can add up indoors.

7. Radon From Well Water

If your home draws water from a private well, radon may enter your home through the water supply. When you run a tap, shower, or use the dishwasher, radon can be released into the air inside your house. 

This is more of a concern in suburban areas, where well water is common. It's also easy to overlook because most radon testing focuses on the air, not the water. So, this source can go undetected for years.

To truly get your home comprehensively tested for radon contamination, contact us at InHaus Lab. We’ll find all the hidden risks in your home. 

8. Lack of Post-Construction Radon Testing

Most builders don’t test for radon once a home is built. There’s no federal requirement to do so, and many buyers don’t think to ask for it either. This is especially true if they’re buying newly constructed homes. 

This means a home can have radon-resistant features installed, check every box on paper, and still have elevated radon levels that nobody knows about. Testing is the only way to confirm if the system is actually working.

EPA Guidelines for Safe Radon Levels 

Because of the above-mentioned reasons, the threat of radon gas in new homes isn’t entirely gone. In addition to knowing how radon can still get in, you must also be aware of the safe and unsafe levels of this harmful gas.

This is what the EPA radon guidelines specify:

Is Your New Home Radon-Free? Find Out With Radon Testing

If you live in a home constructed with radon-resistant features, you may be breathing easier. However, to truly know if your house is safe, radon testing is recommended. With an expert’s insights, you can be sure that your home is not vulnerable to this dangerous gas. 

That’s why radon testing is important.

Want to know if your home is safe? Call InHaus Lab today and book an appointment for radon testing. We’ll check your house thoroughly for this invisible risk. Already, we’ve tested over $100 million worth of homes in Denver, Aspen, Minneapolis, and nearby. 

Radon in New Homes FAQs

1. Is new construction resistant to radon entry?

Not always. While most buildings now include radon-resistant features, they aren’t universally required. So, radon gas may enter new constructions, too. Testing is still the only way to be sure your home is radon-free. 

2. Should I withdraw my offer on a home with high radon levels?

Probably not. Radon levels are fixable. So, ask the seller to tackle the issue before you close your offer, or knock the cost off the price and handle it yourself. 

3. What levels of radon are considered dangerous?

As per the latest EPA radon guidelines, you need to take action if the radon level is 4 pCi/L or more. But no level of this hazardous radioactive gas is really “safe.” Many experts suggest taking action even at readings as low as 2 pCi/L. 

4. What are some radon exposure risks that homeowners should keep an eye out for?

If you spend a lot of time in the basement, live in an area with high radon levels, or have a tightly sealed home, your risk may be higher than average. Still, the only real way to know where you stand is to get your home tested. 

5. What is the importance of radon testing in homes in 2026? 

Radon is still the second leading cause of lung cancer in the US. So, if the gas sneaks into your home, the tight and energy-efficient construction gives it nowhere to escape. That’s why you need to test your home for this lethal gas. 

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References:

• EPA, “Radon-Resistant Construction Basics and Techniques”
• EPA, “Radon-Resistant New Construction for Home Buyers”
• EPA, “Radon Zones Map” 
• Reddit