Radon is an invisible, odourless radioactive gas that seeps up from the ground into Irish homes — and it's the leading cause of lung cancer after smoking. Pick your county and tell us a little about the house. We'll show your area's radon risk honestly, and give you a plain path: the county is only a starting point — the one thing that tells you your own level is a test.
Radon comes from the ground, so risk starts with local geology. County gives a broad indication — pick yours to see the area picture.
Read this before you trust the county tier. Radon is intensely local — two houses on the same road can read completely differently because it depends on the ground directly beneath each one and how the house is built and ventilated. A "lower risk" county still has plenty of high-radon homes, and a "higher risk" county has plenty of low ones. The county tier below is an indication drawn from the EPA's published high-radon-area mapping — not a measurement of your home. For your exact address, check the EPA's interactive map, and to actually know, test.
Check your exact address on the EPA radon map →These don't change the radon in the ground — but they change how much builds up indoors, and how much it matters to your health. They set how urgently you should test.
a) When was it built?Radon is heaviest at ground level, so hours spent sleeping or working downstairs matter most. Bungalows and dormers keep everyone at ground level.
c) Extra factors (tick any that apply) d) Does anyone in the home smoke or vape indoors?Choose your county to see the area's radon risk indication.
The same honest sequence for everyone, whatever your county came out as. Nobody should remediate before they've tested; nobody should ignore it because the county looked "low".
The county tier is a signpost, not an answer. A test is cheap, once-off, and the only thing that tells you what's actually in your air. The option that fits your situation is highlighted.
Test first. Only get a contractor in once a measurement shows you're above 200 Bq/m³ — most homes aren't, and the ones that are usually have a simple fix.
The county tiers here are a plain-language grouping based on the EPA's published radon mapping, which predicts what share of homes in an area are likely to be above the reference level. We've deliberately kept it to broad county tiers rather than inventing a precise percentage for your address, because radon varies far more within a county than the county average can capture — that within-county variation is real, and pretending otherwise would be dishonest. Treat the tier as "how much attention this deserves", not "your number". The EPA's own address-level map is the definitive lookup, and a physical test is the definitive answer. Tiers last reviewed July 2026 — re-check against the current EPA map before relying on them.
Radon is a naturally occurring radioactive gas produced as uranium in rocks and soil breaks down. You can't see, smell or taste it. Outdoors it disperses harmlessly, but it can seep up through floors, cracks and service entries into a house and build up — especially in ground-floor and below-ground rooms, and in winter when the house is sealed against the cold. When you breathe it in over years, the radioactive particles can damage lung tissue.
It's a real, measured public-health issue, not manufactured fear. Ireland's geology gives it among the highest radon levels in Europe, and the EPA estimates radon contributes to around 350 lung-cancer cases a year here. It's the second-biggest cause of lung cancer after smoking, and the biggest cause among people who have never smoked. That said, most individual homes are below the reference level — which is exactly why the sensible response is to test and find out, not to panic and not to ignore it.
Ireland's national reference level for homes is 200 becquerels per cubic metre (Bq/m³). Below that you're within the level at which the EPA advises action; above it, you should take steps to reduce it, and the higher the reading the more promptly. There's no level that's completely risk-free — risk rises with concentration and with years of exposure — but 200 is the practical line for deciding whether to remediate.
The standard method is a 3-month passive test: you get two small detectors by post, leave one in a bedroom and one in a main living room for three months (ideally over winter), then send them back to a lab that reports your average level. It's the gold standard because radon swings day to day, and three months evens that out — expect roughly €30–€60. A plug-in electronic monitor costs more up front but gives an indicative reading within days and keeps measuring, which is handy if you want to watch the effect of ventilation changes or confirm a fix.
Not necessarily, and this is the single most important thing to understand. County tiers are averages over a large, geologically mixed area. High-radon homes exist in every county in Ireland, because the gas depends on the specific ground under your house, how it was built, and how it's ventilated. A low county average lowers the odds; it does not clear your particular home. The only way to rule radon out is a test — which is cheap enough that "probably fine" isn't a good enough reason to skip it, especially if anyone sleeps at ground level or smokes.
Don't panic — high radon is one of the more fixable home problems, and fixing it removes the risk. The most reliable remedy is an active radon sump: a contractor fits a pipe under your floor slab with a small continuous fan that pulls the gas out and vents it above the roofline, commonly cutting levels by more than 90%. Fitted, that's often a few hundred euro up to around €1,500–€2,000 depending on the house. Lower readings can sometimes be brought down just by improving ventilation or fitting a positive-pressure unit. Whatever you do, retest afterwards to confirm it worked.
Less, but not never. Building regulations since around 1998 require radon-protective measures (a barrier membrane, and often a standby sump point) in new homes, so post-1998 houses start with an advantage. But membranes can be punctured or poorly installed, and protection isn't a guarantee — plenty of newer homes still test above the reference level. If you're not sure the measures were fitted or working, a test settles it.
It can come up. Buyers and their surveyors increasingly ask, and a recent test showing a level below the reference level — or evidence that a high level was remediated and retested — is a genuine reassurance that removes an objection. Testing early, and keeping the lab report, turns a potential question mark at sale time into a tick.
Considerably more. Radon and tobacco smoke don't just add up, they multiply: a smoker in a high-radon home carries a far greater lung-cancer risk than either exposure alone would suggest. If anyone in the house smokes, testing (and, if needed, remediating) is one of the highest-value health steps you can take for the household — alongside the obvious.