Buying a home that has tested positive for radon is generally . Radon is a naturally occurring, radioactive gas that can be found in any home, regardless of its age or construction type. While high levels (4.0 pCi/L or higher) are a serious health risk, radon can be effectively mitigated through relatively simple and affordable systems. Understanding the Risks and Requirements Home Buyer's and Seller's Guide to Radon | EPA