It's very location dependent, some areas have low average levels. https://www.epa.gov/sites/default/files/2018-12/documents/radon-zones-map.pdf https://www.epa

It's very location dependent, some areas have low average levels. https://www.epa.gov/sites/default/files/2018-12/documents/radon-zones-map.pdf https://www.epa.gov/sites/default/files/2018-12/documents/ra...