How often should you test your home for radon?

Why bother

Invisible, and the #2 cause of lung cancer. Standard upkeep. Dull and cheap, and a lot less dull than whatever it's quietly preventing.

What the job involves

1. Buy a test. A charcoal kit ($15 to $30, lab fee included) gives a quick read; a long-term alpha-track kit ($20 to $50) sits 90-plus days for a truer yearly average; a reusable electronic monitor ($150 to $400) lets you retest forever for free.
2. Put it in the lowest level anyone actually uses, basement or ground floor, away from drafts, exterior doors, and damp. Shut the house up the way the kit instructions say and leave it the full window.
3. Send the kit to the lab or read the monitor. The EPA's line is 4 pCi/L: at or above that, it needs fixing. The CDC reckons it's worth a think even between 2 and 4.
4. If a quick test reads high, run a second test before paying a soul for mitigation. Radon swings with the season, and you want the real number, not a bad week.

Do it yourself, or pay someone?

The test is yours to do: a $15 to $50 charcoal or alpha-track kit is genuinely accurate if you follow the placement instructions. Hire a pro ($145 to $714, continuous-monitor reads around $300 to $500) when you need a certified report for a house sale or your state wants a licensed measurer. Fixing a high result is always a pro job: about $787 to $1,280 installed.

What skipping it costs

$700 to $1,500 is what it costs to fix a home that tests high, an active soil-depressurization system that pulls the gas out from under the slab, averaging around $1,032 and running to $1,780 on a larger or more awkward house. Radon is invisible and odorless, the EPA's number-one cause of lung cancer in non-smokers and the second overall, tied to roughly 21,000 lung-cancer deaths a year in the US. You cannot smell it, see it, or feel it, so a home above the line keeps quietly dosing everyone in it for years. The test is a few dollars. It exists to catch the expensive, dangerous thing before it sits there unnoticed.

Signs it's overdue

• You have never tested, or it has been more than two years. The EPA and CDC say retest every two years, and after any remodel, foundation work, or change to how the house breathes.
• You finished a basement, added a basement bedroom, or sealed the house up for efficiency. Any of those changes how radon gathers indoors.
• You had a mitigation system fitted but never checked it since. Fans and systems wear out, and the only way to know it still works is to retest.

When to start thinking about it

Give yourself about 7 days' notice. That's when Grumpty starts grumbling, so it doesn't land on you the day it's due. Mark it done and Grumpty sets the next one, every 24 months, so you can go back to forgetting it exists.

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