How much water we need a day?

I suppose you mean to say how much water we should drink in a day and not the overall requirment of water in the house for all the purposes. If I am correct in my guess let me expalain the ody requirment of the water. The need to drink the water related to the conditions below. depends upon.... 1. the cliamet and humidity. 2. the body weight. 3. type of work you do. 4. type of food you eat. 5. overall condition of your health. If all the above condition range in a normal level the water needed would be close to 5 liters a day. Do drink water 30 minutes before the meals and do not drink during and after the meals for atleast upto 2hours. The The water being the first reason for body infections besure of it's hygenic best quality. Pure distilled and minral water is always better for good health. Use clean and hygenically washed containers to store or to drink the water. Avoid bore-well or stagnant water for drinking. Wish you a good health.