Short-Term vs. Long-Term Radon Testing: Which Is Right for You?

Both short-term and long-term radon tests give you useful data — but they're suited to different situations. Here's how to decide which makes sense for your home.

Real Estate Considerations

Real estate transactions almost always use short-term tests because of time pressure. The test typically runs during the inspection period, and results must come back before the contingency deadline.

In Illinois, real estate radon testing is governed by state disclosure rules. Sellers are required to disclose known radon hazards. Buyers should ensure any test was conducted under closed-house conditions and by a certified tester — a test that doesn't meet those conditions may not hold up in negotiations.

After a Short-Term Test Shows Elevation

If a short-term test comes back at or above 4.0 pCi/L, the EPA recommends a follow-up test before proceeding — or moving directly to mitigation if the level is significantly elevated (above 8–10 pCi/L). Your tester can advise which path makes sense for your situation.

Once you have confirmed elevation, a mitigation contractor designs a system to fix it. At that point, the type of original test doesn't matter — what matters is the level found and the construction of your home.