Hi Kumaran,
There are factors that need to be considered in determining the amount of water to drink:
1. If you are a healthy person, then you only need to drink 8 glasses of water or 2 liters daily.
2. If you have heart problems as in congestive heart failure, some types of kidney, liver, or adrenal disease may impair the excretion of water, themn it is required for you to limit your water intake.
3. If you have bladder infection or urinary tract infection, you're an athlete, or very active physically, or you live in a place with high humidity that causes you to perspire too much, then you have to drink more water, maybe 3 liters daily.