SURFACE WATER IS POLLUTED WHERE AS THE GROUND WATER MAY HAVE ADVANTAGES

WATER FOR DRINKING :-- A potable water is one that is safe for drinking and pleasant to taste and suitable for domestic purposes .A contaminated water is one that contains  bacteria and which may causes diseases and a polluted water is one that contains substances which are undesirable and unfit for drinking or the domestic use .The main two sources of water supply are surface water and the ground water where as surface water is a mixture of surface run-off and the ground water includes water of the rivers , springs and the lakes etc .In most instances surface water is subject to pollution and contamination and must be treated before use for drinking purposes .  Ground water or sub soil water is the most important source of supply and may be obtained from the wells often most practical and economical and it is free of pathogenic bacteria and other common impurities and free of colour and turbidity and can be used without further treatment however the water that has travelled a long distance under ground is likely to be more highly mineralised than water drawn a short distance from where it entered the earth , more over all water originates rainfall and rain water is derived from water vapours rising from the seas ,rivers ,lakes etc etc forming into the clouds and then condensing as rain , hail and snow .