Radon and Uranium in Well Water

In this section there is a tale from Winter’s Bay discussing lake water vs well water.

Although the subject here relates to well water, it should be emphasized that radon seeping into a dwelling from the ground is a real health concern. Anyone living full time on the Canadian Shield, as we are at Chandos, should be checking for Radon. It is the leading cause of lung cancer after smoking. Please see the blog posts here regarding the health concern, and here for a primer on what radon is.


As part of the Winter’s Bay condo development planning process, extensive testing was carried out by EXP Consultants on both lake and ground water to determine their potability and suitability as a drinking and domestic water source.
Although the EXP information is site specific, it is an excellent starting point for all Chandos cottage owners wanting to know more about their drinking water.

The most startling outcome of the Haastown/EXP water source study was the rejection of drilled well water because of the presence of uranium and radon.

Just be extremely aware that there is no guarantee that the results actually represent conditions at other sites, and also that conditions can change with time.

The EXP report recommends using treated lake water instead, which appears to be the route that the developer is taking.

Uranium is ingested and can affect  kidney function.

Radon is a gas, which is released from the water and is inhaled, thereby potentially affecting the lungs. Radon also enters a dwelling through cracks etc in the basement.    It is a very complicated subject, as the actual health hazard depends on how much radon is in the home air itself.  eg how much is also seeping into the home from the ground, and what  level of air exchange exists in the dwelling.  Please see the following comments from Public Health Ontario about radon.

Regardless, it seems like a good idea that anyone with a deep drilled well, who lives on the lake year round, should consider having their water tested for uranium and radon. 

See  Tables 1 & 2, pages 12 &13, of the EXP document wintersbay-water-tests7-exp ,   for the lake surface water analysis results, (page 12&13)

See  Table 6 on page 145, along with tables C-1, C-1B, C2, C-2B, starting on page 124 of  the EXP document winters-bay-uranium-well-watertest exp  for the ground water test results, including radon and uranium.

Canada has a max limit (0.02 mg/L) for uranium in well water.  Table 6, p. 145, shows a range of uranium readings, with the highest at Test Well #5 being 0.139 mg/L.  See the Health Canada Document health canada uranium-eng for more on uranium.  It says that reverse osmosis is a remedy.

Canada does not have a criterion for radon in well water,  but some results (max of 410) at Winter’s Bay exceed the proposed US regulatory Guideline of 148 Bq/L.  See the  CDC Radon fact sheet.  There is a remedy for radon gas, involving aeration at point of entry and venting to the outside.