How much water to be taken??

So many experts will specify exactly, how much fats or proteins  or vitamins are needed to our body frequently. But how much quantity of water needed are said only approximately. But one international scientist group has released an exact chart on water intake.

Two hours Before exercise:400-600 ml water should be taken.

Whether we had taken sufficient amount of water or not we can check it before and after doing exercise by measuring our weights.

In body, for every pound(0.5 kg) weight at least 450 to 675 ml water should be taken.

While doing exercise about 150 to 350 ml of liquid should be taken based on body condition.

Who do less exercise will have more water content than who is healthy.

After exercise: the amount of water lost doing exercise should be balanced by taking that much of water.