How can Radon enter my home?
Radon gas can enter a house any place it finds an opening where the house contacts the soil: cracks in foundation walls and in floor slabs, construction joints, gaps around service pipes and support posts, floor drains and sumps, cavities inside walls, and the water supply.
Radon can also be found in groundwater from private or small community wells. Radon produced in the ground can dissolve and accumulate in water from underground sources such as wells. When water containing Radon is agitated during daily household use – showering, clothes washing or cooking, for example – the Radon gas can be released into the air. However, research has shown that drinking water that contains Radon is far less harmful than breathing the gas. The health risk does not come from consuming the Radon, but from inhaling the gas. And in most cases, the risk of Radon entering the home through water is much lower than if it enters through the ground.
Materials used to construct a house – stones, bricks, cement, or granite, for example – are not a significant source of Radon in Canada. Natural materials taken from the ground, like granite, can contain some uranium and may have higher levels of radiation or Radon than expected, but in the vast majority of cases these levels are not significant. In February 2010, Health Canada completed a study of 33 types of granite commonly purchased in Canada and none were found to have significant levels of Radon.
Almost all homes have some Radon. The levels can vary dramatically even between similar homes located next to each other. The amount of Radon in a home will depend on many factors.