Buying or selling a house with radon in Pennsylvania

The buyer tested, the number is 9.2. What Pennsylvania law says, who usually pays, and how to keep the deal together.

Radon comes up in most York County home sales, because inspectors offer the test, the county is Zone 1, and roughly a third of houses fail. It rarely kills a deal if both sides handle it sensibly.

Disclosure

Pennsylvania's Real Estate Seller Disclosure Law requires sellers to disclose known material defects, and the standard form asks about radon testing and results. A seller who has a test result over 4.0 pCi/L, or a mitigation system, must say so. A seller who fixed it and kept the paperwork can disclose it with confidence; a working system is a selling point, not a defect. The DEP publishes a Home Buyer's and Seller's Guide to Radon that most York County agents will recognise.

For buyers

1. Test. Ask your inspector for a 48-hour continuous-monitor test by a DEP-certified tester. It usually adds $150 to $300 to the inspection.
2. Do not panic at the number. 9 or 12 pCi/L is ordinary for York County and is fixed for $1,200 to $1,800. A house at 30 costs about the same to fix.
3. Decide what to ask for. Either the seller installs a system by a DEP-certified mitigator before closing with a passing post-test, or you take a credit equal to a quote and choose the contractor yourself. A credit gives you control; seller-done work is faster.
4. If the house already has a system, test anyway to confirm it works, check the manometer, and ask for the installation paperwork and last post-test.

For sellers

If you have never tested, test before listing, in winter if you can. A high number found on your own terms costs $1,200 to $1,800 and a week. A high number found by the buyer's inspector costs the same plus a negotiation you will lose. If you install, use a certified mitigator, get the post-test, and put both documents in the disclosure packet.

Who pays

There is no rule. In York County the seller usually pays, either by installing or by credit, because buyers treat a high test like any other inspection finding. In a strong seller's market buyers sometimes absorb it. Lenders almost never require mitigation; the FHA and VA do not, and conventional lenders leave it to the appraiser, who rarely raises it.

Timing

A certified mitigator can normally install within one to two weeks and the post-test takes two more days, so a radon contingency of three weeks is realistic. Ask the contractor to run the post-test rather than waiting a month; a short-term test straight after installation is accepted for closing.

After closing

Re-test every two years and after any renovation. If you inherited a system, replace the fan when it dies (about ten years) rather than ignoring a level manometer. See fan replacement and repair.

Last updated 2026-09-28. General information for the York area, not professional advice; confirm specifics with a qualified contractor or your insurer.