I prefer my caffeinated water hot, with the optional coffee flavouring, though caffeinated OJ is a nice idea.
Since we’ve mainly concentrated on asking for proof that Perfect Water is in any way different to ordinary water, it’s true that we’ve not really discussed safety much.
Water is not, usually, considered a harmful substance requiring FDA/FSA approval, whether used as an additive or sold as a product in itself. Certainly there are standards as to what the water can contain, but beyond a minimum purity requirement water is treated as intrinsically safe.
Perfect Water claim that their water has unique properties, that it is different from ordinary water both in physical and chemical nature, and most importantly, that it is biologically active in a way ordinary water isn’t.
So not only is it up to them to prove those claims, but having done so it is up to them to prove that this physically, chemically and biologically novel product is not harmful to humans. In the US, this requires they go through a pre-application process with the FDA and CFSAN, formally apply with data on the chemistry, toxicology (from animal studies), estimated consumption, environmental effects and health implications.
Of course, if they were to maintain that Perfect Water had medicinal benefits, it would be treated as a drug rather than a food, which would mean a considerably more stringent process comes into play, involving not less than three properly controlled and conducted human studies.