More than half of your body is water and everything that happens inside you depends on it. Without water, the body rapidly starts to malfunction, and the effects are noticeable when just two percent of total body water is lost. If the amount drops to over 15 percent, it can be fatal.

• Brain — Water in the central nervous system acts as a shock absorber, protecting the brain and spinal cord from damage. 70 percent or more of our brain is water.

• Defense — Water is used to produce tears, saliva and mucus, helping to protect our bodies from infections and irritants.

• Blood — Water in the blood acts as a carrier, transporting red and white blood cells, gases and nutrients around the body. 50 percent of our blood is water

• Kidneys — The kidneys use water to wash away waste products, like excess salt and urea.

• Digestive system — Water helps to keep food moving through the digestive system, allowing enzymes to access the nutrients inside.

• Skin — Water helps to regulate body temperature by carrying excess heat away from the skin as it evaporates.

• Bones — Bones might look dry, but they are around 25 percent water by weight, helping nutrients to reach the living cells inside.