A CLEAR AND SPARKLING WATER IS NOT NECESSARILY FIT FOR HUMAN CONSUMPTION, HENCE IT IS ESSENTIAL TO DETECT THE DANGEROUS MATTERS BY WAY OF SIMPLE TESTS.

Drinking water must be free from (a) disease producing organisms or harmful bacteria or Micro-organisms as colloidal matter;(b) dissolved poisonous chemical substances of all kinds;(c) objectionable gases -- but may contain good amount of dissolved oxygen;(d) dissolved minerals which impart excessive hardness to water and must not deposit sediment on standing. Drinking water should not contain any appreciable amount of suspended matter. It should as far as possible, be colourless, odourless, cool and pleasant to the taste. Deep well waters may have a slight earthy odour. Pure water, when in large quantities, has a faint bluish tint, peaty water has a brown tint. Any other colour may indicate pollution. Warm waters are generally deficient in oxygen and are therefore somewhat unpalatable. The suitability of a water for any particular purpose can be determined only after a complete analysis and investigation of the source of origin of supply. A complete water analysis consists of four sections: Physical, Chemical, Bacteriological and Microscopic. For drinking water supplies the bacteriological and physical analysis are of prime importance. The microscopic analysis is necessary to determine the existence and extent of organisms that may create taste and odour problems. Raw water contains suspended, colloidal and dissolved impurities. Frequently, water is treated not only to improve its quality from aesthetic and sanitary point of view, but also to reduce its corrosive or scaling properties which would effect the life and carrying capacity of water pipes. Except in a few special cases all surface supplies needs to be filtered, and supplies from the large rivers require rather more elaborate treatment. Filtration is often unnecessary in the case of underground waters which are usually hard and are frequently softened;soft upland waters are hardened. As a final process water has to be sterilized.