water is the major constituent of human being. Water contributes to two third of our body weight.water acts as a solvent, transporting, combining and chemically breaking down the substances.Blood in our body consists a large amount of water and helps to transport food and remove waste material. We use water for drinking, washing, cooking, and cleaning. Many communicable diseases such as dysentery, typhoid, diarrhea, etc. spread from the use of polluted water. We should always use clean and safe water for our daily use to stay free from different types of communicable diseases.