A radon result above 4 pCi/L during a home purchase feels alarming and is actually one of the most routine findings in central Iowa real estate. It is a fixable condition with a known price range — closer to a worn furnace than a cracked foundation. What matters is handling it inside the deal's timeline.
Inspection timelines
Radon testing happens during the inspection period, using a continuous monitor placed for 48 hours with closed-house conditions. Book it the same day as the general inspection — the report lands in time to negotiate, and in Zone 1 skipping the test is the real risk.
If the monitor was placed with windows open or the seller ran fans, the report will usually flag it. A tamper-flagged or borderline result is grounds to retest, not to guess.
Mitigation before closing
The common resolutions: the seller installs a system before closing, credits the buyer the cost at closing, or the buyer accepts the number and handles it after. Any of these works — a credit often works best, because then you choose the installer and own the warranty.
If the seller installs, require that the work include a post-installation test showing the result, not just an invoice that a fan went in.
Retesting and documentation
Whatever path you take, the file you want at the end holds: the original test report, the installation paperwork with the system warranty, and a post-mitigation retest below 4 — ideally below 2.
Keep testing on a two-year cycle after you move in. The system's manometer tells you the fan is pulling; only a test tells you the number in the air stayed down. Both take minutes.
If you are the seller
The same finding reads differently from the other side of the table: a high test is not a deal killer, it is a line item. Getting ahead of it — testing before listing and installing a system on your own schedule — is cheaper than negotiating it under deadline with a buyer's installer quote in hand.
A documented system with a passing retest becomes a selling point in a market where every buyer's agent asks about radon.
Either way, the worst position is the one avoided by testing early: discovering the number for the first time five days before closing.
