Rainwater harvesting is the collection and storage of rain from roofs or from a surface catchment for use in the home or garden.

Rainwater harvesting

Rainwater harvesting is the collection and storage of rain from roofs or from a surface catchment for use in the home or garden. The water is generally stored in rainwater tanks (also known as water butts) or directed into mechanisms which recharge groundwater. In New Zealand houses away from municipal water supplies often rely on rainwater collected from roofs as the only source of water for all household activities. This is usually the case for many holiday homes as well.

There are a number of types of systems to harvest rainwater.

As rainwater may be contaminated, it is often not considered suitable for drinking without treatment. However, there are many examples of rainwater being used for all purposes — including drinking — following suitable treatment.

A diverter is often used to divert the initial flush of rainwater, containing most of the debris from the roof and pipes, goes to waste. Meshes stop insects from breeding. Water can be treated with UV light to kill pathogens and filtered to remove heavy metals.

Rainwater harvesting collection tank

Rainwater collection tank