Radon is an odorless and colorless gas that naturally occurs in rock and soil. It can seep into homes through cracks in basement floors and foundations, crawl spaces, poorly sealed sump pumps, porous cinder block walls, and other foundation floors and wall penetrations.
Radon reduction steps include:
Fill or seal any cracks, crevices, or holes in the foundation.
Provide a tight fitting, sealed lid for the sump pit.