Radon in drinking water

Cathal Walsh
Environmental Blogger
Tuesday, 14th May 2019
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Radon in  drinking water

Radon is a naturally occurring gas that finds its way into water sources. This happens when water passes over rocks and soil that contain radon. Radon is soluble so it then dissolves into the water at this stage.

Radon is formed during the radioactive decay of uranium. It has no colour, taste or smell and can only be detected or measured using special equipment. Ground water from wells and boreholes is most at risk for having a high concentration of radon. Surface water from rivers and lakes is less likely to have a higher concentration of radon.  The EPA recommends that all ground water sources be tested for Radon levels.

The health effects of radon are considered severe. When one consumes radon dissolves in drinking water this results in the radiation from the radon being absorbed into the stomach.  Studies here have not shown a definite causative link between radon consumption and stomach cancer, however it is a general rule that the consumption of radioactive material should be avoided at all cost.

The main way in which radon appears to be harmful to human health is by the inhalation of radon gas. There is a clear and definitive link between radon gas and lung cancer. Radon gas can come from tap water and be released into indoor air throughout a house. This may be a particular problem in homes with bathrooms that have lacklustre ventilation.


The radon dose that can be taken in from drinking radon in water is relatively low when compared to the radiation ingested when inhaling radon in air.  The process of boiling water releases radon from the water, as a result one should not worry about radon when consuming water that has been boiled. Care should be taken however to boil the water in a well ventilated area as radon gas is released when the water is boiled and this should not be consumed.

Radioactivity is measured in becquerels. The EPA  has laid out that for public water supplies, where the radioactivity levels exceed 500 becquerels per litre (Bq/l )  then immediate action should be taken to reduce the level of radon in the water supply.

For private water sources this limit was set at 1000 becquerels per litre. 

How can water contaminated with radon be made safe?

Because radon is a gas it is lost from water over time due to agitation.  For this reason if you install a holding tank, an aeration system or an agitation system between the source of the water and your household tap will significantly reduce thee levels of radon.

How do I test for Radon in my water?

To test for radon in your water you will normally have to bring a water sample to one of our accredited labs  that carries out radon testing.

While it is somewhat laborious to get a radon in water test, the main way you can protect the

residents of your house from the harmful effects of radon is by installing a radon gas detector in your home. Radon gas is a lot more harmful and if radon gas is detected then this

almost certainly indicates the presence of radon in your water supply.  These detectors are not very

costly and are easy to install in the home. 

If you have any concern about the quality of your water head to https://www.h2olabcheck.com/catalog/drinking-water-test-kits

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