What water? My tap water is 4.5 gallons for one cent. If you run reverse osmosis like I do you have to pay 3 times as much because 2/3 of it is "waste." Add the annual $50 for membranes and carbon filters and it comes out to about 4.6 cents a gallon. $3.99 a 12-pack is $3.55 a gallon. Even a case of 40 0.5 liter bottles of water is about $3.75, or 71 cents a gallon. tl;dr: Pabst $3.55/gallon Water $0.05 - $0.71/gallon