Rainwater harvesting is basically the accumulating and storing, of rainwater for reuse, before it reaches the aquifer.
Water collected from the ground, sometimes from areas which are especially prepared for this purpose, is called Stormwater harvesting. In some cases, rainwater may be the only available, or economical, water source. Rainwater harvesting systems can be simple to construct from inexpensive local materials, and are potentially successful in most habitable locations.
Roof rainwater can be of good quality and may not require treatment before consumption. Although some rooftop materials may produce rainwater that is harmful to human health, it can be useful in flushing toilets, washing clothes, watering the garden and washing cars; these uses alone halve the amount of water used by a typical home.
In the UK water butts are often found in domestic gardens to collect rainwater which is then used to water the garden.
However, the British government’s Code For Sustainable Homes encourages fitting large underground tanks to new-build homes to collect rainwater for flushing toilets, washing clothes, watering the garden and washing cars. This reduces by 50% the amount of mains water used by the home.
Above shows a basic rainwater harvester. A simple diagram to show the various parts and functions of a Rooftop rainwater harvesting system. The process shown in the figure makes the collected rainwater suitable for drinking or common household use.