So every time you buy a bottle of water for $1, you are paying 2,279 times what you would if you filled that same bottle with tap water. If most of what you drink is bottled water, assuming you drink 64 oz. of water per day, you’d consume a little under three 20 oz. bottles of water per day. Those 3 bottles per day would cost you $3/day or $1,095 per year. That same 1,095 bottles filled with tap water would cost you $0.48 PER YEAR.