Roof Water Harvesting: Components of Rain Water Harvesting

Water professionals all over the world are increasingly worried about the scarcity of water. According to the UN World Water Development Report of 2003, various factors like climate change, pollution and population growth will result in a sharp decline in the amount of water available per person in developing countries. Hence,

Domestic Roof Water Harvesting (DRWH)

is an effective source of water which meets the local water needs. Read on to know more about the components of roof water harvesting.

‘Rainwater harvesting’ is a term which covers all those techniques in which the rain water is collected and stored for general use. Usually, small reservoirs are constructed to collect run-off water so that it can be used for micro-irrigation and cattle. Even, this run-off water is collected from impermeable surfaces and from roofs. Hence,

roof water harvesting

is a part of rainwater harvesting which has its own importance.

Components of Rain Water Harvesting

The essential components of roof water harvesting are a water storage equipment, a suitable roof and a channel to lead the rain water from the roof to the storage equipment. Additionally, a few rain water harvesting systems have additional components to improve the water quality or manage it effectively. The components include:

The Roof

A ‘suitable’ roof means that it should be constructed with hard building material. It should not contaminate the run-off or absorb the rain. The most effective materials are plastics, metal sheets and tiles. Palm-leaf and grass are not recommended for water harvesting. Also, the run-off flow is big if the size of the roof is large.

Water Storing Equipment

Mostly, better performance is seen in a roof water harvesting system which has a large water store when compared to a small store. In the rainy season, a small store like a 500 litre container will tend to overflow. Also, it will become dry by the end of summer.


It is an arrangement to lead the rain water from the roof to the water store. It is also known as downpipes or gutters. These are open channels that carry the rain water sideways under the roof edge to the water store.

Other Components

Some of the other components of roof water harvesting include pumps, level gauges, overflow arrangements, filters and screens.

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