Water is used in almost all cosmetic products as a solvent: dissolves other ingredients and makes emulsions (a Main 8 that will be explained in another post). Therefore it is found in lotions, shampoo and conditioners, skin care products, creams, makeup, etc. It is usually listed as the first ingredient on the label due to its high concentration but it is not usually listed as water. Instead, it is called aqua or distilled/purified water because the water that scientists use is completely microbe, toxin and pollutant free.
However, studies have found that only 10% concentration of water on the outermost layer of skin is all that is needed to keep the skin soft. In fact, externally, water dries out the skin by evaporating with the natural oils that skin produces thus drying out the skin. Therefore, the water that is in these cosmetic products is not the moisturizing agent but rather acts solely as a solvent and a component to the formation of emulsions.