Generally the water used for cooking is not used as drinking water
for making this water fit for drinking we need proper water treatment
some common water treatments
1)Boiling
It is the most commonly used method of water purification.Boiling of water kills microorganisms like bacteria and make the water fit for drinking
2)chlorination is another method for water treatment, by adding chlorine bleach water can be made fit for drinking
3) UV water purification : By using ultraviolet radiation in water the microorganisms can be killed, this is a very fast method for water purification
4)Distillation : Distillation of water involves boiling of water into steam and condensed back into liquid in a separate container. It is safe for Drinking
There are many other ways for water purification like iodine treatment, reverse osmosis,ozonation etc