Water has two classic roles in all living matter; life giving properties & life sustaining properties. Roughly 60% of the adult body is made of water. Drinking enough water helps maintain the body's fluid balance, which helps transport nutrients in the body, regulate body temperature, and digest food and much, much more.Reduction of Excess Body Weight: Choosing to drink sufficient daily quantities of good quality water (8 glasses or 2 quarts) versus other liquid options leads to increased weight loss as well as overall improved health.  Fereydoon Batmanghelidj, Water for Health, for Healing, for Life: You're not Sick, You're Thirsty! (Grand Central Publishing, 2001), 99-104.
Muscle Fuel: when muscles don't have enough water they get tired. Drinking water provides that much needed extra energy. In actuality water is a primary source of energy!  Ibid. 16-18.
Kidney Function: Our kidneys process 200 quarts of blood daily, as it sifts out waste & transports urine to the bladder. Yet kidneys need enough fluids to clear away what we don't need in the body. Drinking 2 quarts of water a day helps to get the job done!
Fatigue Fighter: Most fatigue is caused by dehydration. Water not only restores energy far more efficiently than coffee, it also relieves those tired eyes!
Pain Prevention: Pain is often a sign of dehydration. A little water can go a long way toward preventing and/or relieving aching joints, muscle cramps, strains and other body stressors.
Clearer skin: certain toxins in the body can cause the skin to inflame, which results in clogged pores and acne. Water flushes out these toxins and can reduce the risk of pimples.
Reduction of Stress Induced Illness & Depression: The brain depends on two mechanisms. The brain uses electrical energy (1) that is generated by the flow of water (2). With dehydration, the level of energy generation in the brain is decreased. Many functions of the brain that depend on this type of energy may become inefficient which can lead to poor coping choices and/or depression. Drinking sufficient quantities of water can help avert this lack.  Ibid. 58.
Brain Boost: A study in London found a link between students bringing water into an exam room & better grades, suggesting water promotes clearer thinking.  The University of East London. (2012, April 20). Bring water into exams to improve your grade. Retrieved May 21, 2013, from The University of East London: http://www.uel.ac.uk/news/press-releases/2012/04/waterexams.htm