Rainwater harvesting simply collects the rain which falls onto roofs, then stores it in a tank until required for use. When required, the water is then pumped to the point of use, thus displacing what would otherwise be a demand for mains-water.
The rainwater is brought to a central point, via normal guttering and down-pipes, to enter a storage tank (frequently underground), where it is filtered on entry. A highly efficient and reliable submersible pump delivers the water to a service on demand.
The size of the storage tank is determined by considering the amount of water available for storage (a function of roof size and local average rainfall), and the amount of water likely to be used (a function of buildings occupancy and use)
As well as being ENVIRONMENTALY FRIENDLY, collecting and using your own water can SIGNIFICANTLY REDUCE YOUR WATER BILLS.