Frequently asked questions


Radon is a naturally occurring, radioactive noble gas. It is formed by radioactive decay from uranium, which is found in all soils and rocks. As a gas, radon escapes from the soil and mixes with the air. Radon is odorless, colorless and tasteless and cannot be perceived by humans.

Radon enters the indoor air of buildings from the building subsoil through cracks and fissures in the foundation. Radon can also be released from building materials. High radon concentrations can occur in buildings under unfavorable conditions. Outdoors, on the other hand, radon dissipates quickly.

The World Health Organization (WHO) classifies radon and its derivatives as a proven carcinogen. Radon is thus on the same level as tobacco smoke and asbestos. In addition, radon is the largest contributor to the average radiation exposure of humans in Austria. After smoking, radon is the most frequent cause of lung cancer! In people who have never smoked, radon is even the most common cause of this type of cancer. According to current knowledge, other health complaints are not caused by radon.

Strictly speaking, the radon secondary products lead, polonium and bismuth are responsible for the harmful radiation exposure. As a gas, radon remains in the respiratory tract only briefly and is quickly exhaled again. The radon progenies, however, remain in the moist respiratory tract. The radon secondary products can damage cells in the lung tissue and thus lead to lung cancer.

Radon measurements in private households

Only a measurement of the radon concentration in the indoor air of your house can provide clarity. No two houses are alike, as the radon concentration depends on various factors. These include the geological composition of the soil, the construction of the building and the ventilation behavior of the occupants. No two houses are alike. To determine the radon concentration, you must perform a long-term measurement.

The Federal Ministry for Climate Protection, Environment, Energy, Mobility, Innovation and Technology (BMK) enables a free radon measurement with two radon detectors in your private household as part of its activities for radon protection. For these measurements, the BMK provides a contingent of radon detectors twice a year. For further information on free radon measurement in private households, please click here.

A long-term measurement takes about six months. This records diurnal and seasonal fluctuations in the radon concentration in the house. More than half of the measurement period should fall within the heating season.

The measurement is carried out with two radon detectors in the two most frequently used living rooms. The measuring devices must remain in the same room for the entire measurement period. However, the living rooms should be used normally.

No, the radon detector does not need to be switched on. Simply take the radon detector out of the packaging. The radon detector will start measuring from that moment.

No, radon detectors are not dangerous, do not make noise and do not radiate. They are about the size of film canisters, are made of plastic and do not require a power supply.

The two radon detectors are placed in the two most used living rooms, because the radon concentration should be determined where you spend most time, which is usually the living room, children's room, bedroom or kitchen.

No, radon measurement in unoccupied basement rooms is not useful. The radon concentration should definitely be measured in the two living rooms where you spend most of your time. Note: However, if one of the two most used living rooms is in the basement, for example a child's room, the measurement can take place there.

Radon detectors should be placed out of reach of children and animals. Basically, a free place should be chosen for the detectors which:

  1. is not directly next to a window or door (avoid drafts),
  2. is not heated (by sunlight or heating),
  3. is at least 10 cm away from the wall and floor.

Please note that the detectors must remain in the same room for the entire measurement period.

Measurement result

In principle, the radon concentration indoors should be as low as possible. However, there is a reference value. This is 300 becquerels per cubic meter of air (Bq/m³) and refers to the annual mean value of the radon concentration.

Radon concentration is measured in becquerels per cubic meter of air (Bq/m³). The unit Becquerel describes the average number of atomic nuclei that decay in one second. Example: A radon concentration of 300 Bq/m³ means that 300 radon nuclei decay in one cubic meter of air per second, emitting radiation.

In this case, there is no need for action.

Note: If you are planning renovations or conversions (replacement of windows, full thermal insulation, breakthroughs in the foundation area), discuss the topic of radon with the company carrying out the work. This is because structural changes to the building can lead to an increase in the radon concentration indoors.

If there is too much radon in your house, action is required!

As an initial measure, regular cross-ventilation and shock ventilation in the living area or the conversion of rooms can help. There are simple and proven methods to permanently reduce radon concentrations. For initial information, contact the Austrian Agency for Radon or your provincial building department! Currently, there are no companies in Austria that specialize in radon remediation. Training of specialists in structural radon protection is currently under development.

No, there is no limit value. There is no threshold below which radon is no longer harmful to health. Therefore, the lower the radon concentration, the better.

New construction, renovation, house purchase

Yes, radon protection is regulated by building legislation in all federal states.

There are various building measures for protection against radon, which are specified in an Austrian standard (see ÖNORM S 5280-2 Radon - Technical precautionary measures for buildings).

Basically, the tighter the building envelope is designed against the ground, the lower the radon risk. Preventive measures are also much simpler, cheaper and more efficient than retrofitting. Consult a professional to find the best solution for your new house.

Note: A control measurement is recommended after completion of the building.

Note: Upper Austria promotes precautionary measures for new buildings in the radon risk area

The measurement of radon in soil air (soil gas measurement) is technically possible in principle. However, it is not recommended because it is very complex and cost-intensive, but not very meaningful. The radon concentration depends not only on the soil gas concentration, but also on the construction of the building. It is easier and more effective to install precautionary measures in new buildings.

Radon precautionary measures are mandatory in Austria.

The province of Upper Austria has published a brochure for precautionary measures in new buildings and general renovations.

Simple radon remediation costs a few hundred euros. If the remediation measures are more complex, costs of up to 10,000 euros can be incurred. Measures range from sealing components such as the floor slab to extracting the soil air below the floor slab. Various measures are listed in ÖNORM S 5280-3 Radon - Remediation measures for buildings.

Note: After radon remediation, a control measurement is recommended.

Note: Upper Austria, Styria and Tyrol promote structural remediation in case of high radon concentrations.

If possible, clarify the radon situation with a long-term measurement. A long-term measurement takes about six months and should be carried out during normal room use. A measurement is therefore only useful in occupied rooms.

Short-term measurements are not recommended, since no meaningful comparison with the reference value is possible.

Tip: What you should consider when buying a house

Radon in drinking water

In most cases, drinking water has no effect on indoor radon concentration.

Only in individual cases can radon dissolved in water lead to increased radon concentrations in dwellings, for example if the water supply is from the home's own well or if the water is piped directly from the source into the house. However, the contribution to the total radon exposure is usually negligible. Incidentally, the Drinking Water Ordinance regulates how high the radon concentration in drinking water may be. Official controls are carried out on a regular basis.