Radon map - MO CountiesSee U.S. interactive map

Did you know that high levels of radon, a naturally occurring gas that we breathe every day, is the 2nd leading cause of lung cancer?

Did you know that it is easy to find out if the radon rate in your home is dangerous?

Did you know that it is easy to fix elevated radon levels in your home?

As a real estate agent, I’ve been helping clients test their future homes for radon for years. Compared to other problems you might discover in your home, the cost is reasonable if you do find a problem and need to have a radon mitigation system installed.

For about $175, you can have your home professionally tested to know if you have a problem that needs to be addressed. If you do have elevated levels of radon in your home, you can have it mitigated, eliminating dangerous radon gas levels, for around $700 (extremely large homes will be a little more expensive).

There are also DIY test kits available for a lot less money. I wouldn’t use these during a real estate transaction, as there would be no way of knowing if the home seller carried it outside during the test to reduce the radon level for the results. But, it is a good inexpensive solution to testing your home for yourself.

I used a similar kit to test the radon level in my first home. By the time I bought my second home, I knew all about radon and had it professionally during the inspection period.

What are the Radon Levels in St. Louis?

Missouri is identified by the EPA as having moderate risk. This means that there is good chance that a MO home will have radon levels higher than 4.0 pCi/L, the level established by the EPA as putting your health at risk.

NOTE: The World Health Organization sets the acceptable level of radon at 2.7 pCi/L.

St. Louis Home Radon Levels


Radon Level (pCi/L)


% of Homes above
4.0 pCi/L


% of Homes above
2.0 pCi/L

Missouri Counties: 
St. Louis City 2.5 17.8% 48.2%
St. Louis County 4.0 28.8% 56.6%
St. Charles County 4.0 27.5% 54.5%
Jefferson County 5.3 37.0% 67.3%
Franklin County 3.4 32.8% 60.2%
Warren County 4.1 35.1% 61.4%
Lincoln County 4.0 33.0% 60.8%
Illinois Counties:
Madison County 4.0 34.5% 64.3%
St. Clair County 4.5 40.4% 67.2%
Monroe County 4.9 39.8% 67.5%

What does this mean?

If you live in St. Louis County, almost 1 in 3 homes have radon levels above the level the E.P.A. defines as safe.

Your risk of living in a home with high radon levels is lowest in St. Louis City and highest in Jefferson County, MO or the Illinois counties of St. Clair or Monroe.

Does this mean that St. Louis City homeowners don’t need to test their homes?

Absolutely not.

While your chances of having a home with a radon issue is lower, if you happen to live in the 1 in 5 home that DOES have a dangerous radon level, you are putting yourself and your family at risk for lung cancer even if you do not smoke. If you are a smoker or former smoker, your risk for getting lung cancer is even higher.

People who live in rental homes, new construction homes or ground level condos should also have their homes tested.

Dr. Oz has a video that does a great job of explaining what radon is, how it gets into your home, and how it can cause lung cancer. Take a look at this video and then click here if you want to buy one of the DIY radon test kits.

If you live in the St. Louis area have high levels of radon in your house, contact me and I can suggest a reputable company to solve your problem.

Disclosure: This blog post contains advertising. If you click the link for the radon test kit and decide to buy something at Amazon (the test kit or something else), I will get paid a tiny amount of money which will help me get closer to my dreams.