Housing Authorities

Please note that in early 2019 the Reference Level for radon in workplaces reduced from 400 Bq/m3 to 300 Bq/m3This reduction is on foot of regulations to implement Council Directive 2013/59/Euratom (Radiological Protection Act 1991 (Ionising Radiation) Regulations of 2019). Therefore if the measured radon concentration in a workplace is greater than 300 Bq/m3 remedial action is required to reduce those levels to below 300 Bq/m3.

Radon is a radioactive gas. It has no taste, colour or smell. It is formed in the ground by the radioactive decay of uranium which is present in all rocks and soils. You cannot see it, smell it or taste it. It can only be measured with special detectors.

The World Health Organisation has categorised radon as a carcinogen, in the same group as asbestos and tobacco smoke. In Ireland, approximately 300 cases of lung cancer each year are linked to exposure to radon. There is a synergistic effect between radon and tobacco smoke. This means that smokers are at much greater risk of developing radon related lung cancer than non-smokers. There is no scientific evidence linking radon with any other types of respiratory illnesses or other cancers.

Outside radon is diluted to very low levels. Radon can enter a home from the ground through small cracks in floors and through gaps around pipes or cables. Homes in some parts of the country are more likely to have a radon problem. These parts of the country are called High Radon Areas. You can check our interactive map to see whether your social homes are in a High Radon Area. We advise testing all social homes, starting with those in High Radon Areas.

The acceptable level, or Reference Level, for homes in Ireland is 200 becquerel per cubic metre (Bq/m3). For workplaces, the Reference Level is 300 Bq/m3.

Health Risks

image of radon lungs Over a long period of time, exposure to radon can increase your risk of developing lung cancer. Radon produces tiny radioactive particles. When they are inhaled these particles can be deposited in the airways and result in a radiation dose to your lungs. There is a synergistic effect between radon and lung cancer. This means that smokers are at much greater risk of developing radon related lung cancer than non-smokers. 

The risk of developing radon related lung cancer

Your risk of contracting lung cancer from exposure to radon depends on:

  • how much radon you have been exposed to
  • how long you have been exposed to this level of radon
  • whether or not you are a smoker (smokers are at 25 times more risk from radon than non-smokers)

Learn More

To find out more read our health leaflet.

My Responsibility

As a landlord, each Local Authority and Housing Association has a duty of care to its tenants. This includes minimising the risk from radon. The EPA has developed guidance notes to help Local Authorities and Housing Associations develop a radon testing programme. It also includes advice about reducing radon levels where necessary and communicating the results of this programme.

What is my responsibility to employees?

Find out about employers responsibility to their staff.

Testing for Radon

The only way to know if radon is a problem in a home is by having a radon test

Please watch our video to see how easy it is to test your home for radon.

A radon test is carried out by placing two small detectors, about the size of a matchbox, in a home for three months. One detector is placed in a bedroom the other in a living room - the places most occupied by the tenants. After three months, when the detectors are posted back to the laboratory, they are analysed to see how much radon they have been exposed to in the home.

The results of the radon test will then be posted to the homeowner. If the results are high, advice on what to do next will also be included.

Radon levels can vary a lot between buildings so it is necessary to measure all homes in an estate individually. The EPA has developed guidance notes to help Local Authorities and Housing Associations develop a radon testing programme. It also includes advice about reducing radon levels where necessary and communicating the results of this programme.

image of radon detector Buying a radon test

The EPA provides a list of registered radon testing services.

Retesting a home

Where a home has tested below 200 Bq/m3 there is no need to re-test unless major refurbishment work is carried out on the home. For example fitting new windows or building an extension and other such work that could in theory open up new entry routes for radon or prevent radon escaping from your house. It is also recommended that a home is retested when there is a change in occupancy.

The EPA recommends that homes that have tested above the reference level of 200 Bq/m3 and have carried out the necessary remediation work should be retested every 5 years to ensure the remedial work remains effective.

Reducing High Levels

If the results from your radon test show that the radon levels in your home are high there are a number of simple ways that you can reduce these levels.

Please watch our video to see how easy it is to reduce radon levels in your home.

The best way to reduce radon depends on the levels in your home and the building type. Here is a guide to the methods most commonly used:

image of vents Improving indoor ventilation

One of the simplest ways to dilute moderate levels of radon is to increase the indoor ventillation by installing wall vents or window trickle vents. This can reduce radon levels in a home by up to 50%. It is important that increased ventilation is installed at ground level only as additional ventilation on upper floors may increase the flow of radon from the ground into the home. This work usually costs in the region of a few hundred euro.

Improving under-floor ventilation (for homes with suspended floors)

If a home has a suspended floor you can also reduce the amount of radon entering the building by increasing the sub-floor ventilation. Clearing or replacing existing sub-floor vents or installing additional vents or airbricks will increase the flow of air below the floor and so reduce the amount of radon entering the home. This work usually costs in the region of a few hundred euro.

image of subfloor vent











 image of subfloor vent active




















Installing a passive sump

image of passive sump For radon levels up to 400 Bq/m3, a passive sump can reduce radon levels by up to 50%. A passive sump is a sump system that works without the action of a fan. Instead, wind action over the top of the sump-pipe (which often is fitted with a rotating vane or ventilator) draws radon up through the sump system. 

Installing an active radon sump

The most effective and most commonly used way of reducing the flow of radon into your home is by installing an active radon sump. A radon sump is a cavity about the size of a bucket immediately under the floor slab that is linked by pipe work to the outside. The radon rich air coming from the ground is drawn out from under the floor slab by a small electric fan in the pipeline and vented to outside before it is drawn into your home. This can reduce radon levels in a home by about 90% and sometimes up to 99%. An active radon sump can usually be installed in one day and all the work is carried out from outside the home.The work typically costs about €925, but this can range from €400 to €1500, depending on the complexity of the work. The annual running cost of the fan depends on the power of the fan used. The running costs range from about €30 using a 14 watt fan to about €150 for a 70 watt fan. Typically an active sump can reduce radon levels by about 90% but this may range from 60% to 99%.

image of active sump added and outlet at eaves

Getting the work done

The EPA provides a list of registered contractors who will be able to advise you about the most suitable solution for your home.



Discuss the following issues with the contractor:

Testing the home following remediation work

Fan maintenance (for active sumps)

Costs of running fans (for active sumps)

Retesting following significant building work on the home

It is important to have the home re-tested after the work has been completed, to ensure that it has reduced the radon levels in the home.

To find out more read out booklet on radon remediation.

Normally remediation is successful at the first attempt. However, sometimes more work is needed to reduce the radon levels to below 200 Bq/m3. It is a good idea to agree with the contractor what steps may be taken if the radon levels remain high.

There is no absolute certainty that radon will be reduced to below 200 Bq/m3 even following a number of remediation attempts. While this rarely happens, it is important to note that any significant reduction in radon levels will reduce the risk of lung cancer even if the levels are not reduced below 200 Bq/m3.

image of active sump with fan at ground level

Maintenance of remediation systems

For active sump systems it is important to discuss the choice of fan with the contractor. It is also important to ensure that passive ventilation systems remain clear from debris.

Radon Prevention

image of standby sump If your home was built after 1st July 1998, the building regulations require that it is fitted with a standby radon sump. This is simple pipe work that extends from under the foundations into the outdoor air. If high radon levels are measured, the standby sump can be activated by adding a fan.  It should be noted that a standby sump that has not been activated by adding a fan does not reduce radon levels in your home.

For houses built in High Radon Areas the installation of a radon barrier as well as a standby sump is required. The installation of these protective measures is not a guarantee that radon levels will be below 200 Bq/m3. The EPA recommends that a radon test is carried out within the first year of a new home being occupied. 

 image of radon membrane


Radon tests

Registered radon testing companies charge between €40 and €89 for a radon measurement.  

Remediation costs

At present, there is no grant available to assist with the cost of radon remediation. Some radon reduction techniques are more expensive than others. Typically the cost to retrofit a radon sump is about €925 (ranging from €400-€1500). Other, less expensive options are available, for example, improving the ventilation in your home by installing extra wall vents. This type of work usually costs in the region of a few hundred euro.

A Scheme of Housing Aid for Older People is available to assist older people, generally over 66 years, to have repairs or improvements carried out to their homes. Where a suite of works is being grant aided under this scheme, Local Authorities may also, as part of the package of works, assist with the provision of radon remediation works, where applicable. Contact the Housing Section of your Local Authority for further information. Additional information is also available from Citizen Information website.




Further information about radon is available here:

EPA guidance document for Local Authorities

Radon in homes leaflet

Radon in workplaces leaflet

Understanding Remediation booklet


Radon Services

Registered Radon Remediation Services

The EPA has developed a registration scheme for radon remediation services.  Registered remediation contractors have met a number of requirements including attendance at a training course on remediation, followed by a successful assessment, adherence to a code of practice, tax compliance, appropriate insurance, etc.


Registered Radon Measurement Services

A registration scheme for radon measurement services has also been developed. Further details are available in this guidance document and registration form.

The EPA provides a list of registered measurement companies

To determine whether the radon levels in a workplace exceed the Reference Level the Regulations require that the test should be carried out over a minimum period of three months. For homes a minimum three month measurement is also recommended by the EPA. For these measurements, the use of passive detectors is generally the most cost effective and the most straightforward approach.