Radon Testing and Mitigation: What Every Homeowner Should Know

TL;DR: Radon is an invisible, radioactive gas and a leading cause of lung cancer — and the only way to know your level is to test.

_Last reviewed: July 2026 · 2 min read_

Radon is a colorless, odorless, radioactive gas that seeps up from the ground into homes — and it's the second-leading cause of lung cancer in the U.S. You can't see or smell it, so the only way to know your home's level is to test. Four things to understand: test regularly, test the right spot, read the number, and mitigate if it's high.

How often should I test for radon?

Test at least every two years, and also after major foundation work, renovations, or moving into a new home. Levels change over time and vary by season and home. Inexpensive DIY test kits and digital monitors are widely available, and many areas offer free or low-cost kits. The U.S. EPA's radon program is the authoritative resource.

Where in the house should I test?

Test the lowest livable level of the home — the basement or ground floor where people spend time — since radon enters from the ground and is highest down low. Follow the kit's instructions: keep windows closed during a short-term test, place it away from drafts, and don't disturb it. Testing the wrong spot gives a misleadingly low reading.

What does the radon reading mean?

Radon is measured in picocuries per liter (pCi/L). The EPA recommends taking action to reduce levels at or above 4.0 pCi/L, and says you may consider reducing levels between 2 and 4. Outdoor air averages around 0.4 pCi/L. Know your number against these benchmarks — a high reading is a health issue worth acting on, not ignoring.

How is high radon fixed?

If levels are high, consider a radon mitigation system — most commonly "sub-slab depressurization," a vent pipe and fan that draws radon from beneath the foundation and releases it above the roof, away from living space. It's installed by a certified radon professional and is highly effective. Sealing foundation cracks helps but isn't a substitute for a proper system.

A health note: radon is a genuine health risk, and this is general information, not a substitute for testing and professional advice. If your level is elevated, contact a state-certified radon mitigation professional.

Keep your test records

Logging your radon test dates and readings tracks your home over time and matters at sale. Okoniq Property Hub keeps it with your home maintenance records in one private place.

Frequently asked questions

Is radon really dangerous?

Yes — long-term exposure to elevated radon is the second-leading cause of lung cancer after smoking, per the EPA. The risk is from years of exposure, which is why testing and fixing high levels matters.

How much does radon mitigation cost?

A mitigation system typically runs a few hundred to a couple thousand dollars depending on the home — modest against the health risk. Get quotes from certified professionals.

Okoniq Property Hub helps homeowners and landlords keep maintenance, bills, and contractor info in one calm place. Get started free.

FAQ

How long does a radon test take?

Short-term radon tests take 2 to 7 days, while long-term tests run 90 days to a year and give a more accurate average. Short-term tests are fine for an initial screening, but a long-term test better captures seasonal variation.

Can I test for radon myself or do I need a professional?

You can absolutely test yourself using an inexpensive DIY kit from a hardware store or online, or a plug-in digital monitor. Professional testing is an option but not required for initial screening.

Does every state have high radon levels?

No — radon risk varies widely by region and geology, with some states and counties showing much higher averages than others. The EPA publishes radon zone maps, but every home is different, so testing your specific property is the only way to know.

Will a radon mitigation system make noise or use a lot of electricity?

The fan in a sub-slab depressurization system runs continuously but is quiet and uses about as much power as a standard light bulb, typically adding only a few dollars per month to your electric bill.