what drinking a gallon of water a day does
Number of Ounces to Drink to Reach a Gallon. 16 8-ounce glasses of water equal one gallon. Photo Credit 16 8-ounce glasses of water equal one gallon. There are 128 ounces in a gallon, so to drink a gallon of water in one day, you would need to drink 16 8-ounce glasses. It seems like an impossible task, but recent research suggests that a person who drinks a lot of water every day enjoys better digestion and may lose weight quickly.