Before you begin
What affects radon risk in a home
Answer the testing question first. A three-month result already in hand outranks every other signal here, and a home that has one is never asked where it is.
For an untested home, the area lookup reads the EPA's own radon risk map at the location you give. That location is used for the lookup and is not stored, put in the page address or written to a log.
The county is the fallback, not the main event. It ranks what testing found across a whole county, and radon varies far more within one county than between two.
Count hours at ground level: a downstairs bedroom, a home office or bungalow living is where exposure accumulates.
Reading the answer
Understanding your test priority
Every route ends in a measurement. The EPA recommends that every home is tested, so what this changes is how soon — and what to do with the answer once it arrives.
The EPA's map predicts what share of homes in an area exceed the level: about 1 in 5, 1 in 10 or 1 in 20. Only the first is a High Radon Area, and even there most homes are below the level.
The reference level for a home is 200 Bq/m³. It is compared against the seasonally corrected average of two detectors left in place for at least three months.
Below that, nothing further is needed until new windows, an extension or insulation work. Above it, the level is reduced and the home retested — free from the EPA after remediation, then every five years.
Boundaries
Assumptions and limitations
Working assumptions
- An EPA area classification is read as the share of homes it predicts above the level: 20%, 10% or 5%. The same three bands then apply to it as to a county's measured share, so the precise route arrives with no scale of its own.
- County bands rank the EPA's own measured record. They start at the EPA's 10% High Radon Area line, but they are not that classification, which is drawn on geology at a far finer resolution than a county.
- Where the home is is capped at a quarter of the score whether it came from the map or from a county, because the EPA's position is that an area never predicts a house.
- Build era, ground-floor hours, a basement and low ventilation raise how urgently a home should be tested. They do not raise the level a test will find.
- Smoking does not change the radon in a home. It multiplies what that radon does, which is why it raises the priority rather than the reading.
- "Not sure" about the build era is scored as unprotected, because nothing was required before July 1998.
Where to be careful
- The EPA's map predicts an area, not a house. High readings occur in low-risk areas, and most homes inside a High Radon Area are below the level.
- The area lookup needs the EPA's mapping service to answer. When it does not, the result says so and falls back to the county record rather than failing.
- A device position fix coarser than half a kilometre is refused rather than mapped, because the EPA's areas are drawn finer than that.
- The county figures count homes whose occupiers chose to test, so they run higher than the county as a whole.
- This is a priority and a route, not a radon measurement. Nothing here can clear a house.
- Workplaces are compared to 300 Bq/m³ and must be tested by law in a High Radon Area. Schools run on the Department of Education's own arrangements. This tool covers homes.
Worked example
The same question, answered end to end
A never-tested home the EPA maps as a high radon area, built before July 1998, in ordinary daily use, where someone smokes.
What was entered
- The EPA radon risk map returned a high risk area for this location.
- Built before July 1998, and never tested for radon.
- Ordinary daytime use at ground level, no basement, no recent draught-proofing.
- Someone in the household smokes.
How it is worked out
The EPA predicts about 1 in 5 homes in this area — 20% — above the reference level. That is at or above the 15% top band, so where the home is starts the score at 2 out of a possible 8. It is also above the EPA's 10% line, so this is a High Radon Area.
Built before July 1998, so no radon protection was required in it: +1, taking the score to 3.
Ordinary daytime use at ground level, no basement and no recent draught-proofing each add nothing.
Someone smokes in the home. The EPA puts the radon risk at 25 times greater for a smoker at the same radon level, so this is the largest single factor: +2, taking the score to 5.
5 reaches the top band, so the priority is High: two detectors for at least three months, read against 200 Bq/m³, and a kit costs about €40 to €60.
What the tool returns
- Priority
- High
- Your next step
- A three-month test
- Area lookup
- EPA local area
- EPA radon area
- High risk
- Level to act at
- 200 Bq/m³
- Typical cost
- €40 to €60
Common questions
Questions about this tool
What happens to the Eircode or location I give?
It is sent to a Verdanyx endpoint, used once to find which EPA radon area contains that point, and then discarded with the request. It is never stored, never written to a log, never put in the page address and never returned to your browser — the answer that comes back is the EPA's classification for the area, which is public. You do not have to give one: choosing a county, or nothing at all, still produces a result, and the result says which of the three it used.
How is a home radon test actually done?
You buy a kit from an EPA-registered testing service and place the two detectors it contains — one in the main bedroom, one in the living room, the rooms people spend most time in. They stay there for at least three months, then go back to the laboratory. The average of the two rooms is seasonally corrected and that corrected figure is compared to 200 Bq/m³.
What does a radon test cost in Ireland?
About €40 to €60 for one kit, which covers both detectors and the laboratory analysis. The EPA publishes the list of registered testing services; it stopped running its own measurement service at the end of 2019.
My home was built after 1998 — is it already protected?
Only partly. Since 1 July 1998 every new building must have a standby radon sump, and the EPA is explicit that a standby sump does not reduce radon until a fan is fitted to it. A radon membrane is required on top of that only in a High Radon Area, and a membrane can be damaged during construction. Post-1998 homes in high radon areas measure about 25% lower on average — lower, not clear.
What happens if the result comes back above 200 Bq/m³?
The level is reduced and the home retested. Extra wall or trickle vents cost a few hundred euro and can cut levels by up to half; an active radon sump typically costs about €1,200, is installed in a day mostly from outside, and typically cuts the level by around 90%. If the home already has a standby sump, fitting a fan to it is about €1,000. The EPA then provides a free post-remediation test, and the home is retested every five years.
Is there a grant for radon work?
No. There is no radon grant. Where a local authority is already funding a package of works under the Scheme of Housing Aid for Older People, radon remediation can be included in that package — contact the housing section of your local authority.
Do landlords, buyers or sellers have to test?
There is no legal requirement for a private landlord to test a rented home, or for an owner to test or remediate before selling. A seller's solicitor does ask whether a test was done and whether anything was reduced, and passes the answer to the buyer. Because a test takes three months, test well before putting a home on the market — and, as a buyer, test again after moving in, since radon levels depend on how a house is heated and aired.
Can I get a free radon reading before paying for a test?
Some libraries lend digital radon monitors through an EPA scheme. A monitor gives an indication of the level in one room over days, which can be enough to decide whether to act sooner. The EPA is explicit that it is not a replacement for the three-month test: only a three-month result, seasonally corrected, can be compared to 200 Bq/m³.
Can a home in a low-risk area still measure high?
Yes, and this is the single most important thing to take from the result. The EPA's map predicts the share of homes in an area, so a low-risk area still means about one home in twenty is expected to be above the level, and high readings do occur outside mapped high radon areas. Two homes on the same street can differ. A physical test is the only answer for one address.