They all get run through filters anyway. Some water companies use tap water, more or less, run it through their filters and slap packaging on it. Think multi-billion dollar companies lol. I think I know the rainwater company he's speaking about, and if it is that one then if say it's the best water I've had. As far as how pure it is, don't have a clue. You gave an amazing answer and he'll spend the end of days answering#2. Blind taste test you can't really tell one from the other anyhow. RMHB had about the best coconut water I've had, and it's from a can. I think they'll do fine with water. Most don't really give a damn where the water's from, as long as it taste good to them.