Question: how many liters do i have to drink to make a gallon?
Answer: There are 3.7854118 liters in a gallon, because by definition one gallon is 231 cubic inches and one liter equals to the volume of one kilogram of water (1000 mL or 61.0237 cubic inches), that makes 231 / 61.0237 = 3.7854118 liters in a gallon.