Next to air, the other important requirement, for human life to exist is water. It is essential for life, health and sanitation. It is the principal raw material for food production. It is needed for drinking, bathing, washing of hand, face, floors, wash­ing of cloth, flushing of W.C., gardening (17000-35000 Lit/day/hectre) Vehicles & road washing, fountain, heating, air conditioning, swimming pool, air cooler, brewing, coffee, cleaning of equipments, utensils, ice making Fire fighting etc. In hotels water requirement is 180 Lit/bed/day. In restaurant water require­ment is 70lit/seat/day.