Water is important to cells because without it they would not be able to remove waste, bring in nutrients or transport oxygen. The body is a very intricate system where many parts rely on each other. Without the cells being able to perform or move oxygen around the body, death would be quick to follow the loss of the water.
The human body is made up of 60 to 70 percent of water. Most humans can go up to seven days without water, but past that they are at risk for death. This occurs because the body starts to lose water from the blood first so the transportation of oxygen slows and sometimes stops, which leads to the shutting down of organs in the body. The human body can start to shut down and begin to die with as little as nine to 12 percent water loss. Water is often called a solvent because it is key to so many processes where it acts as exactly that, a solvent. It helps to break waste and nutrients down in the cell so that they can be moved through the various membranes and natural filters in the body. If the water did not assist in breaking these down then the cells would not be able to function properly.