Rainwater harvesting is a very simple concept where the rainwater from the roofs of buildings is filtered and collected in a storage tank. The storage tank can be either underground or over ground, typically a domestic system is underground with commercial and agricultural systems located over ground. The water in the storage tank is then re-used in place of potable drinking water. Typical applications include:
Garden Irrigation: Watering flowers, car washing, outdoor cleaning etc.
Domestic Use: Flushing toilets, cleaning, laundry etc.
Domestic Use: Supplying drinking water to animals, water reserve for spraying, washdown etc.
Commerical / Industrial: Flushing toilets, cooling for industrial machinery, wash plants, etc.