How Does Radon Get Into My House?

 

 

Radon gas is completely natural. It forms during the natural decay of uranium 238 ore in the soil. The uranium ore becomes radium, which then becomes radon. When it becomes a radon atom it is a gas. Because of this factor, it can seep from the ground into the air in a house. The primary way that radon enters a house is through the lowest level (crawl space, basement, slab) by a variety of paths:

cracks in basement floors
drains
sump pumps
exposed soil or gravel
construction joints (mortar, floor-wall)
loose fitting pipes

Radon may also enter the air of a house from well water, but this is a minor source compared to that coming in through the lowest. Some parts of the United States have higher risks of radon than others. The U.S. Environmental Protection Agency has a map that shows which counties and states have higher average radon levels. You can see the national map here or the Illinois map here.