Mayo Clinic recommends that women consume approximately 2.2 liters of water each day, and an average of 3 liters for men. These totals include water obtained from all beverages, as well as food.
Personal water needs depend on many factors, including health, level of activity and location of residence. About 80 percent of people's total water intake comes from drinking water and beverages, including caffeinated beverages, and the other 20 percent is derived from food. Prolonged physical activity and heat exposure increase water loss, and therefore may raise a person's daily fluid needs. Excessive amounts of water can be life-threatening.