Since the beginning of time, water has continued tobe an important thing to all living things. Without water nothing could live. We may change our food according to the climate of a place but we find no substitute for water. Man has always looked for pure fresh water to slake his thirst. Water not only quenches our thirst but it is also a source of food to us. From the sea we catch large quantities of fish and other creatures. We use water to irrigate our lands to produce crops. Many parts of the world are dry and barren because there is no water there. People in such places lead a very hard life. Even the plants and animals find it a real struggle to survive. They can obtain water only by some means of ingenuity.