Human body can store fat, but not water. One can become fat and can also become dehydrated, if there is no regular intake of water. Human body tends to lose 2500ml of water every day, but retains fat. Hence, everyday water has to be replenished and make up for the loss. 20kgs of weight = 1 liter of water. If you are 60 kgs, then drink 3 liters of water. Keep this formula in mind and drink water daily according to your weight.