The human body is made up of between 50 to 75 percent water based on sex and body type. Our brain is made up of 85% water. Staying hydrated is one of the most important things we can do as all of our organs depend on it whether we're being active or not. The Mayo Clinic has found that the average water intake for a man is 3 liters.  But staying hydrated and not being thirsty isn't the only benefit, your overall health can improve by drinking enough water.