Our body consists for an average of 70% of water. Part of it is in our blood, or intercellular, the remainder is needed for the functioning of our organs. Each separate part also consists mostly of water:
 90% of the brains (for some a bit more...)
 79% of heart and lungs,
76% of the muscles,
70% of the liver
22% of the bones and even
10% of the teeth is water.
The total amount of water in the body of an average adult is 37 liters. It helps our joints and eyes staying moist and is necessary for the chemical processes that occur in our cells. Water is for a body like oxygen, it’s vital. Water is a universal solvent and transport medium, and is the basis of all biological processes in the human body.

Water regulates the temperature of the body. If you have a fever, it is good to drink plenty of water. Water removes waste from the human body.
Water leaves the stomach five minutes after it is drunk.

‘Although man exist for 70% out of water, abstainers are still not satisfied.’(John Hendrick Bangs)