Why not phone in an order to Staples--The water is like $6.00 per case with free shipping and will be waiting for you when you arrive.
16 oz. equals 1 pound.
Actually, you're closer to the true weight than you think but the logic is a bit off. There are two types of ounces in English units of measure, which makes things confusing for a lot of people.16 oz. equals 1 pound.