That is interesting. I'm just a complete beginner at Japanese, but I always found it interesting and unusual that you have two words for water: お湯 and 水. The word I learned as a beginner was みず. When I looked it up in a dictionary a few weeks after learning it, I saw a definition like this: "water (esp. cool, fresh water, e.g. drinking water)" This really surpassed me, since we don't have a special word to indicate the water is cool, drinking water. I later learned that the kanji for that word was 水. But I remember thinking that if this word was used mostly for cool, drinking water, then there must be a word that is used more often in other cases. This must be お湯. Do I have that right? The way I think of it in English is that if the water is already hot, you might not need to boil it!