A fluid ounce in the US is defined as a 1/128th of a US gallon, meaning that 128 / 16.9 =7.57 bottles containing 16.9 US fluid ounces of water each will make up exactly 1 US gallon. How many bottled waters equal a gallon …. hi i have found that when the weather is cool drinking so much water is difficult, can i drink Let’s get straight to the point: There are 128 ounces in a gallon, so to drink a gallon of water in one day, you’d need to drink 16 eight-ounce glasses.If you want to really ensure you’re drinking a gallon of water a day, try getting a 1 gallon water bottleand fill it each morning. If you finish it before bed every night, ..1 gallon = 4 quarts = 128 fluid oz. So normally there are approx. 12 oz in a bottle of water, so you would have to drink at least 10 bottles of water … 1 US gallon = 128 US fluid ounces so divide 128 by 16.9 to get the answer hope that helps. Bottled water comes in many different sizes, so you might need to be more specific. I buy the 500ml bottles, and it would take about 8 of them to ..How many water bottles of poland spring are in a gallon? Poland Spring water. How tall is an average 16.9 fl oz Poland Spring Water bottle? A 16.9 fluid ounce.