Rainwater Harvesting

Today, water is becoming an expensive commodity. As a result of increasing demand water reserves are falling, the amount available to us is declining and water charges are continuing to increase year on year. Up to 50% of the treated water that is currently used can be safely replaced with rainwater without any loss in convenience.

 

Rainwater, often referred to as soft water, can be efficiently harvested, stored and used for laundry, flushing toilets, general cleaning and garden irrigation.

Calculating available Rainwater Storage.

For a rainwater holding tank we use the following sizing calculation:

Roof Area (square metres) x Annual rainfall (in mm) x Run-Off co-efficient (a pitched, tiled roof is 0.75) x System efficiency (Assume 90%).= Annual collection in litres.

 

A tank is normally sized to store about 5% to 10% of this total to prevent stagnation.

 

The rainwater harvesting systems (RWH) we use are manufactured by GRAF in Germany and marketed under the Garantia brand. The underground systems range from 1600 to 6500 litre tanks. We can also supply and install the DAB Aquaprof ranges and Active Switch.