An adult man's body is made up of 60% of water and that of an adult woman's body contains 55%. Drinking of water helps to maintain proper level of body fluids in the body which in turn results in proper metabolic functions. It is known that an adult person should drink at-least 8 glasses of water per day. Is that correct? The amount of water a person should drink per day depends on his or her body weight, age and physical conditions of the body. Considering this fact, Mayo Clinic , one of the world's renowned medical institutions has derived a formulae for the calculation of amount of water a person should consume based of his / her body weight and age.