Radon testing before buying a home
Understand what a radon result means, when to retest and how to handle mitigation during a purchase.
What matters before you decide
Ask for previous radon reports, then evaluate whether they were recent, correctly performed and relevant to the lowest level you plan to occupy. EPA recommends testing homes considered for purchase and recommends fixing a home at 4 pCi/L or more. Use a qualified tester and mitigation professional where appropriate, and resolve timing and responsibility before the contract deadline.
- Request the full test report, not just a number.
- Retest when location, age or conditions make old results uncertain.
- Discuss mitigation at or above EPA’s action level.
- Check local disclosure rules and the contract deadline.
Read the test in context
Radon is an invisible gas that can enter buildings from the ground. A map or neighboring house cannot establish the level inside the home you are buying. Ask for the device type, location, test duration, date, result and any conditions that may have affected the test. EPA notes that a buyer may request a new test if an old one is not recent, renovations occurred or a lower level will be occupied.
Short-term tests can be useful during a transaction but need correct conditions and interpretation. A qualified provider can explain whether a follow-up test is appropriate, especially near a decision threshold. Do not substitute an informal reading for a documented test.
Plan the response before closing
EPA recommends fixing a home if the radon level is 4 pCi/L or higher and says even lower levels can carry risk. Ask a qualified mitigation contractor about the proposed system, price, permits where required and a post-installation verification test. Agree in writing on who pays and when the work and follow-up test occur.
Keep reports, installation documents and later retest results with the property file. State disclosure rules and contract rights vary, so confirm them locally rather than assuming that a test result alone determines whether you can renegotiate or cancel.
Decision checklist
- Previous reports and test conditions obtained.
- Lowest occupied level and test date checked.
- Qualified follow-up or mitigation scoped if needed.
- Responsibilities documented before contingency deadline.
Frequently asked questions
01Does a low-risk map mean testing is unnecessary?
No. EPA recommends testing the individual home because indoor levels vary.
02Does a mitigation system end the need to test?
No. Verify performance after installation and retest as recommended.
Primary sources and further reading
Always verify the date, scope and local application before using a source for a specific decision.
Independent educational information. Not legal, tax, lending, or investment advice. Verify local rules and consult licensed professionals before making a real estate decision.
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