Radon myths and facts

Radon attracts a lot of half-truths. Here are the common ones, checked against EPA guidance.

“Only old or drafty houses have radon.”

False. EPA says any home can have a radon problem: new or old, well-sealed or drafty, with or without a basement. Newer, tighter homes can even hold radon in more effectively. The soil under the house and the pressure difference that draws soil gas inside matter more than age.

“My neighbor tested low, so I’m fine.”

Not necessarily. Radon levels can vary sharply between neighboring homes because of differences in soil, foundation, and ventilation. Your test is the only reliable answer.

“My county is Zone 3, so I don’t need to test.”

False. EPA says its zone map should not be used to decide whether a home needs testing, and notes that elevated homes exist in Zone 2 and Zone 3 counties. See the zone map explained.

“Radon only matters in the basement.”

Partly true. Levels are usually highest on the lowest level, which is why EPA recommends testing the lowest lived-in level. But radon can move through a house, and homes without basements can have high levels too.

“Radon causes headaches or breathing problems I would notice.”

False. EPA identifies lung cancer as the health effect of radon, developing over years. There are no immediate symptoms to warn you, which is why testing matters. See radon health risks.

“Granite countertops are a major radon source.”

Not shown by current data. EPA says any granite can contain some uranium and may contribute variably to indoor radon, but that existing data are insufficient to conclude that the types of granite commonly used in countertops significantly increase indoor radon levels. Soil gas is the usual source. If you are concerned, test your home’s air; that measures radon from every source.

“Fixing radon costs a fortune.”

Usually false. EPA says most homes can be fixed for about the same cost as other common home repairs, and systems can lower levels by up to 99 percent. See how mitigation works.

“Sealing cracks will solve it.”

Rarely on its own. Sealing helps a mitigation system work better, but EPA does not recommend sealing alone as a reliable way to reduce radon.

“Test the lot before you build.”

Not recommended. EPA says soil tests are not reliable predictors of indoor radon in the finished house. Build radon-resistant, then test the home. See radon-resistant new construction.

The one fact that matters

Testing is cheap and easy. Start with our testing guide.

More myths worth clearing up

"Radon makes you feel sick, so I'd notice." EPA says there are no immediate symptoms from radon exposure. Lung cancer, the only health effect definitively linked to radon, usually appears 5 to 25 years after exposure. You can't rely on how you feel.

"Kids are at greater risk than adults." EPA states there is no evidence that children are at any greater risk of radon-induced lung cancer than adults. That's not a reason to skip testing: everyone in the home is exposed.

"Radon causes asthma or other breathing diseases." According to EPA, there's no evidence that other respiratory diseases, such as asthma, are caused by radon exposure. Lung cancer is the concern.

"Radon is heavier than air, so it stays in the basement." EPA notes radon is about 7.5 times heavier than air, but it's easily moved by air currents and pressure. In homes with forced-air heating and cooling, it can be distributed throughout the house. Upper floors are often lower but not radon-free.

"Venting radon at ground level is fine." EPA disallowed ground-level discharge because radon could re-enter the home and children could be exposed near the outlet. Discharge concentrations can be extremely high, but they fall to near background a few feet from a discharge point above the roof.

"The average house is fine, so mine probably is." The national average indoor level is about 1.3 pCi/L, according to EPA, but averages hide wide variation. Only a test tells you your level.

"Radon only harms smokers." Smoking greatly multiplies the risk, but EPA estimates about 2,900 of the roughly 21,000 annual radon-related lung cancer deaths occur among people who have never smoked. EPA calls radon the number one cause of lung cancer among non-smokers.

Fact-checking radon claims you see online

When you read about radon, look for:

• A source. Is the claim tied to EPA, a state radon program, or peer-reviewed research?
• Units. U.S. sources use picocuries per liter (pCi/L), and many other countries use becquerels per cubic meter (Bq/m³). 4 pCi/L is about 150 Bq/m³.
• Sales pressure. Be cautious of claims that you must buy a particular product. Basic tests are inexpensive, and mitigation should be done by qualified professionals following recognized standards.

Bottom line

The facts are simple: radon is common, invisible, and odorless. It's linked to lung cancer, it's easy to test for, and it's fixable. EPA says some radon reduction systems can reduce levels by up to 99 percent, and most homes can be fixed for about the same cost as other common home repairs.

Quick reference: myth vs. fact

Myth	Fact
You'd notice symptoms	No immediate symptoms, and lung cancer typically appears 5 to 25 years later (EPA)
Only basements matter	Forced-air systems can distribute radon through the house (EPA)
Kids face more risk	No evidence of greater risk for children (EPA)
Only smokers are affected	About 2,900 deaths a year among never-smokers (EPA)
Fixing it is unaffordable	Most homes can be fixed for about the cost of common home repairs (EPA)
Your zone tells you your level	Test every home, regardless of zone (EPA)

If you're not sure where to start, test first. Every other decision depends on that number.

Your state radon program can often point you to low-cost or free test kits.