OP is excluding drinks that aren’t regular water, this isn’t complicated.
If you went to a restaurant and asked for water, what would they give you? Probably something from the tap, or a bottle, or a purified pitcher. Maybe mineral water, but that’s as much additive as you’re going to get. It wouldn’t even be sparkling, and they’re certainly not going to give you milk and smugly tell you “well TECHKNIQUELLY its water!” you damn dork. You know what OP means, you’re being ridiculous.