I'm not sure it is important to be boiled water - at least, not in this country, where most tap water is potable. I'd reckon it is more important to get fluid into the patient than wait for water to cool down enough to drink. Plus boiled water tastes yuk (notice the difference between a cup of coffee made with fresh water, and with re-boiled water). I would suggest the only purpose of the hot water is to help the salt and sugar dissolve. Therefore take a *small* amount of hot water to do this, and top up with cold.