In alt.solar.thermal Robert Gammon wrote:
Not Canada, Australia has the spec

http://www.dux.com.au/tech_domestictemp.htm

I thought that was because of the peculiarity of bacteria in the wooden
dams that hold the water supply for the area around Sydney, NSW.

Certainly not a worldwide norm.

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Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8,-122.5