I use reverse osmosis (RO) water when I make kombucha. We're on a well (so no chlorine), have an iron filter in addition to the water softener.Are you on city water, or well? That would determine whether the water is chlorinated or not.
Tea is only mildly acidic, typically. Kombucha tea is MUCH more acidic than the typical - but adding it to lots of water would have reduced that considerably. OTOH, Kombucha is a ferment process, meaning alcohol - and we all know alcohol is a rather effective generic antibiotic, antimicrobial, antiseptic type product.
I think the alcohol in my kombucha is negligible. I made the SCOBY from a bottle of GT's "for everyone" line, ie, trace amounts of alcohol, and you don't need to be 21 to buy it. I can say that in all the years I've been making and drinking it, I've never gotten a buzz of any kind from it.