You can't see it. You can measure it.
Radon is a colorless, odorless gas that seeps up from the soil under a house. A 48-hour test tells you the number. That is the whole job, and it is worth doing before you own the place.
Add radon to my inspection
One monitor. Two days. One number.
What the number means
Low. Most buyers stop here and move on with their lives.
Below the action level, but the EPA suggests you consider fixing it. Worth a conversation.
At or above the EPA action level. Mitigation is the normal next step, and it is a routine, fixable job.
Reference levels from the U.S. EPA. We report the measurement; a licensed radon mitigation contractor sizes any fix.
Questions we get at the closing table
Does a high number kill the deal?
Rarely. Radon mitigation is a common, well-understood repair. It becomes a negotiating item with a clear scope and a price, not a reason to walk away.
Why a basement test if nobody lives down there?
Radon enters from the ground, so the lowest level shows the highest reading. We place the monitor in the lowest level a buyer could reasonably use.
Do I need to stay out of the house?
No. The house has to stay closed up normally during the test, which is exactly why the number reflects how you will actually live there.
How is this different from a hardware-store kit?
A continuous monitor records hour by hour, so one odd hour does not decide the answer. You get a logged average and a report, not a lab mail-in and a two-week wait.