Average water intake should be 2 to 3 litres minimum.....unless you don't have any water retaining disease. Water requirements is directly proportional to physical activity undertaken. People who take high protein foods on daily basis should also consume more than average. Water is best consumed on empty stomach, before meals and between two meals. With meals one should consume only half glass and instead of water, one can consume thin consistency buttermilk. Immediately post meal one should consume half glass of water..... Should drink water after one hour.