Why is radon a problem in drinking water?

Radon is soluble in water and thus may be taken up by water as it passes over rocks and through soil.  You can be exposed to radon through drinking water and through inhaling radon gas as it is released from water.

• Inhaling the gas
  • Radon is easily released from water into the atmosphere when the water is agitated or heated
  • When you are exposed for a long period of time to high levels of radon, you increase your risk of developing lung cancer.
• Drinking water with high levels of radon
  • The cells in your stomach could be exposed to increased radiation by drinking water that contains radon.

Is my drinking water at risk?

• If you get your drinking water from a borehole or private groundwater supply, then your water may be at risk of having elevated levels of radon.
• If you are connected to the mains supply and get your water from a surface water supply (water from a river or a lake), the risk that your water contains elevated levels of radon is very low. This is because radon is easily dispersed from water when it is agitated as it goes through the mains system; or when left to stand for some time, in a tank or reservoir.

What can I do to protect myself?

• The RPII recommends that if you use water from a borehole or private groundwater supply, you have the levels of radon in your drinking water measured
• For public water supplies, where radon levels are found to exceed 500 Bq/l, remediation of the water supply to reduce radon levels should be carried out
• For private water supplies, where radon levels are found to exceed 1000 Bq/l, remediation of the water supply to reduce radon levels should be considered

Can elevated levels of radon be removed from drinking water?

There are two basic water treatment methods for the removal of radon. Both methods are capable of over 95 per cent reduction.

• Aeration - This is based on the natural tendency of radon to diffuse out of water into the air. Aeration systems include multistaged bubble aeration, high pressure air injection, and spray aeration. Adequate ventilation is then required to prevent the build-up of radon in the air.
• Granular Activated Carbon Absorption - Water is pumped through a bed of granular activated carbon which absorbs the radon. This system has the disadvantage that radioactivity can build up in the unit, which may require specialist disposal.

More information on radon and drinking water

• Read our factsheet on radon and drinking water
• Contact us if you cannot find answers to your questions on our website.