The water (from the Latin aqua) is a substance whose molecule consists of two atoms of hydrogen and oxygen (H2O). It is essential to the survival of all known forms of life. The term water generally refers to the substance in its liquid state, but it may be in solid form called ice, and a gas called steam. Water covers 71% of the surface of the cortex terrestre.2 is localised mainly in the oceans where it concentrates 96.5% of total water, glaciers and ice caps have 1.74%, the underground reservoirs (aquifers ), the permafrost and continental glaciers account for 1.72% and the remaining 0.04% are distributed in decreasing order among lakes, soil moisture, air, reservoirs, rivers and loved vivos.3 Water is a common element solar system, a fact confirmed by recent discoveries. Can be found mainly in the form of ice, in fact, is the base material of comets and their tails up steam.