Multiple choice general knowledge How much water is contained in the human body? 2 Gallon 10 Gallon 15 Gallon 5 Gallon Reveal answer Fill a bubble to check yourself B Correct answer Explanation The human body contains approximately 40-42 liters (10-11 gallons) of water in an average adult. The 10-gallon figure is approximately correct. This tests basic knowledge of human biology and body composition.