Chemist here.
Bottled water is literally just tap water from somewhere else, processed with the same standards (or LOWER standards, since municipal water has to obey both state and federal regulations and bottled just has generic, loose FDA screenings), put in a bottle, and driven a few hundred miles for no reason.
In other words, you're drinking literally exactly the same stuff, you're just arbitrarily burning something like a quart of gasoline and a few ounces of coal and producing a few ounces of kinda-but-not-really recyclable polymer waste per gallon of water for no reason.
The only reason to drink bottled water is if you're fine with tap water but also hate the environment and willing to go out of your way and spend extra money JUST to damage the environment, for no actual benefit to yourself.
(Above assumes you live in the modern first world... but frankly, if you're in central Africa or Mexico or something, don't drink bottled water there either, drink weak beer or pasteurized juice or something else you know is sterilized as a matter of standard processing. The "just tap water from somewhere else" rule applies there, too.)
