The body is about 60 water, give or take. Were constantly losing water from our bodies, primarily via urine and sweat. There are many different opinions on how. Gallon is unit of volume in imperial and US customary systems. The US gallon is defined as 2. Gallon is the largest volume unit in US customary and imperial measurement systems. An imperial gallon is officially defined as equal in volume to 1. Fahrenheit 1. 6. Celsius with barometer at 3. The imperial gallon is 1. US gallon. The abbreviation is gal. Fluid ounce is an imperial and US customary measurement system volume unit. Fluid ounce is the smallest unit of volume in imperial and US customary systems. UK fluid ounce equals to one twentieth of a pint and US fluid ounce equals to one sixteenth of a US pint. The abbreviation is fl oz. DpvdfnsOOP0/VVZWTL2LfjI/AAAAAAAAHeU/H7Bw3w483Is/s1600/gallonrobotpages.png' alt='How Many Cups Of Water In A Gallon' title='How Many Cups Of Water In A Gallon' />There are 128 ounces in a gallon, so to drink a gallon of water in one day, you would need to drink 16 8ounce glasses. It seems like an impossible task. If scroll down, you may also create and print your own custom conversion table create your table.