Do radon levels change over the years?

I purchased my house four years ago and had a radon test that was under 4.0. We are now selling and the inspector tested the radon and it is at 6.6. How can this be?

Tonya - Oak Creek


Hi Tonya,

The EPA recommends testing for radon every two years because things do change. The weather can have a lot to do with your radon levels as well as changes in your house. Radon gas is trying to come up through the soil and seeks the past of least resistance similar to water is trying to go down and seeks the path of least hesitance to find its way back into the soil. Frozen ground or rain saturated soil will not allow the radon gas out so it tends to move into the house so that it can release the pressure. Therefor on a rainy day the radon may be higher than typical and when the ground is frozen the radon may be higher than typical. On the flip side if we have had a dry spell the radon gas will tend to move through the soil instead of the house. High and low pressures can have an effect on radon levels as well as windy days that may create a vacuum in the house. Lastly anything you may have done to improve your house like new windows and doors or installing bathroom and kitchen exhaust vent fans can increase the radon levels in your home. I hope this answers your question.