With purity of around 4 parts per million, rainwater is ideal for pole based window technology.
Many window cleaning companies now use water fed pole technology. These systems require ultra clean water wich is achieved using specialist filter equipment.
The process unfortunately means using 100% more water than is required to fill a wfp storage tank due to waste run off.
Using rainwater which has been collected, filtered for leaves/moss etc and has stood for a day or two elimintes the waste run off issue almost entirely.
As the water collected is unbelievably clean, the wfp system filters have to work less hard and thus have a longer life.
Storage from 750 litres upwards either above or below ground.