The short answer
A high radon reading is a negotiating point, not a dealbreaker. Unlike wiring or plumbing, radon doesn't affect your insurance or your mortgage, and the fix is a standard system that reliably brings levels down. Read the full guide to radon.
Why radon is so common — and so fixable
Radon seeps up from the ground, so any home can have it, new or old — Health Canada estimates a meaningful share of Canadian homes test above the 200 Bq/m³ guideline (recent figures suggest as high as roughly 1 in 5 in some regions). The point isn't the prevalence; it's that a high reading is settled with a cheap test and a routine fix, not a decision to walk.
What testing and mitigation cost
A DIY long-term test kit is about $30–60; a professional test is more. If you're above the guideline, a certified mitigation system (a sub-slab vent fan) typically runs ~$2,500–3,500 and brings levels well down. That's your negotiating number — small, predictable, and permanent.
When to pay a little more attention
Radon is worth taking seriously (not walking, just handling) when the reading is very high, when the basement is or will be a bedroom or full living space, or when you want confirmation — in which case pay for a certified long-term test rather than relying on a quick one. The health risk is real over years of exposure, which is exactly why fixing it is worth it.
How to handle it in your offer
- Make a radon test a condition of the offer where timing allows, or test right after closing.
- If it's high, get a mitigation quote from a C-NRPP certified professional.
- Use the quote to negotiate a credit or have the seller install the system.
- Re-test after mitigation to confirm the level dropped.