Radon: the invisible cancer risk 7 in 10 Irish buyers never test for (2026)

It's the most serious health risk in Irish house-buying that almost nobody checks. Radon — a colourless, odourless radioactive gas — causes about 350 cases of lung cancer a year in Ireland and is the leading cause after smoking, according to the Environmental Protection Agency. Roughly a third of the country sits in a high-radon area. And yet awareness is going backwards, and the overwhelming majority of buyers walk through a viewing without ever asking the one question that a €50 test could answer.

What radon is — and why it's a buyer's problem

Radon forms naturally as uranium in the ground breaks down. Outdoors it disperses harmlessly; indoors it can accumulate, seeping in through floors, cracks and service entries and building to levels that damage the lungs over years of exposure. It is Ireland's single largest source of radiation exposure for the public.

Here's the catch for buyers: you cannot see it, smell it or feel it. It will not show up on a structural survey, a BER, or anything you notice on a second viewing. Whatever level the house has, you inherit it the day you get the keys — and the people most exposed are the ones who spend the most time at home, which after a purchase is usually you.

Awareness is actually falling

The uncomfortable trend, from the EPA's National Radon Survey 2025: awareness of radon has dropped from 82% in 2020 to 71% in 2025. More than half of people don't know radon is linked to lung cancer at all — and even among those who do, fewer than half have ever tested their home. The EPA has been issuing county-by-county appeals urging households to test, precisely because the message is fading just as the risk stays exactly where it was.

Where it's a problem in Ireland

Radon risk is not uniform — it tracks the geology beneath you and varies sharply from one area to the next, sometimes within the same town. The EPA's radon map grades the country down to small areas, showing the percentage of homes predicted to be above the reference level. Parts of the west, midlands and south-east carry notably higher predicted exposure than the national average. Because it's so local, the only number that really matters is the one for the specific address you're bidding on.

The good news: cheap to find, usually cheap to fix

Unlike most things that surface late in a purchase, radon is one of the easiest to deal with — if you check. A long-term test is a small detector left in place for about three months, costing in the region of €50; some local-authority libraries now lend digital radon monitors for free. If a reading comes back above 200 Bq/m³, remediation is usually straightforward — a radon sump or improved sub-floor ventilation — and commonly runs about €800–1,500. That's a line item, not a deal-breaker.

What to do before you bid

Check the area's radon band as part of your homework on any property — the same way you'd look at price, BER and flood risk. If the address is in a high-radon area, treat a test as standard: either budget for one, or make a clear radon test a condition of sale once you go sale-agreed. The cost is trivial next to the purchase, and on a high-radon area it's the one invisible risk you should never skip on the assumption that “it's probably fine.”

BuyerIQ surfaces the radon band for any Irish address — alongside flood, fair value, the bid range and every other risk you can't see at a viewing. Check a property →

Sources: EPA — Radon, Health risks, National Radon Survey 2025. Related: Environmental profile of Irish property areas.