Water a vital resource, it is usually tasteless, odorless, colorless, and a liquid in its pure state.  Water is also one of the best solvent materials.  Almost any substance will dissolve in water to some degree.  That is why so many impurities (gases, solids, and color) are found in the usual sources of water.  It is very rarely that water can be used by industry without treatment.

AVAILABILITY AND DISTRIBUTION:               

Water is most prominent substance for all living organisms. All microorganisms, animals, plants and human beings need water for survival. About 2/3^rd of human body contains water. It plays a vital role in metabolism (release of energy by synthesis of food), in circulatory system, in disposal of waste from body. Practically water is the only substance that occurs in all three common states of matter.

Around 2/3^rd (71 percent) of the earth are covered with water. But unfortunately around 97.6 percent of this is sea water which is unusable for practical purposes. In the remaining 2.4 percent of usable water around 1.9 percent lies in poles as ice caps & glaciers.

TOTAL AVAILABLE WATER IN THE VARIOUS COMPONENTS OF THE HYDROLOGICAL CYCLE

Therefore management of this available water is of utmost importance as water acquires a very important place in nature and in survival of all living organisms. In other words we can say it is the need of the hour.