Collection of rain water from paved or G.I. corrugated roofs and paved courts yards of houses, known as rainwater harvesting, is common in areas having high rainfall intensity well distributed in the years. Such areas include: Himalayan areas, north eastern states, Andaman and Nicobar Islands, Lakshadweep, Rajasthan and southern parts of Kerela and Tamil Nadu.
Rainwater harvesting is now being increasingly used for meeting the drinking water needs of rural areas, particularly during the periods of drought.
Many methods are available for harvesting of rainwater. The choice of a method depends upon the suitability of a particular site. Following steps are followed in rainwater harvesting from roofs:
1. Collection of rainwater
2. Separation of first rain flushes
3. Filtration of rainwater
4. Storage of rainwater
5. Distribution of water
Before supplying for human consumption, the raw water from the pond should, however, be filtered through a sand filter and kept in a PVC tank connected to a hand pump for withdrawal. Despite certain limitations, rain water harvesting will be beneficial for providing drinking water to human beings as well as cattle in areas lacking alternative sources.