Regular amounts of clean, pure water are an absolute must if life is to be sustained. Water makes up more than one-half of the total composition of the mature animal's body and is involved in almost every metabolic process. Blood, the medium by which nutrients are carried to various parts of the body, is approximately 80% water. Water serves as an efficient solvent in cells where the major biochemical processes of digestion, assimilation, metabolism and respiration occur. Water is necessary for the regulation of body temperature and is valuable in the elimination of waste from the body.

Without proper water intake, tissues dehydrate and digestion, along with other metabolic processes, is severely altered. The body's cells, which derive their oxygen from the bloodstream, are starved as the blood becomes concentrated. If just one-tenth of the body's water is lost, death will result.