Chris - I always use boiled water cooled to a temp I can tolerate and do the same with patients. My reason is I think it tastes better than straight tap water - I doubt there is a scientific reason to do it that way but it does need to be warmer than luke warm if that makes any sense? You can always cool the boiled water by adding some cold tap water if you don't want to wait for the water to cool on it's own. It can take a little to get used to though...

MG