Plumbing Africa June 2018 | Page 52

50 FEATURE He says that if the water harvested is to be used for flushing toilets or urinals, or for an irrigation system, a booster pump will be needed to give sufficient pressure to pump the water from the storage tanks back into the main supply feeding the toilets or urinals. “For rainwater designs where the water is also used for urinals and toilets, we include a bypass system where you can switch it back on to municipal mains. If there is a system failure, for example a pump stops working, all that is required is to open your municipal valve and the water will flow back into the main line again. Both lines need to have non-return valves. It is also recommended to have a main domestic water supply feeding the tanks to top it up when there are high volumes, or in the dryer months where rainfall is much less. It is quite important that you have a water bypass system on every installation for residential and commercial use,” says Brainin. Domestic installations for harvesting rainwater. STORAGE TANKS It is the norm that where rainwater is concerned, the storage tanks are placed above ground, but in exceptional cases, if you do not have storage space available above ground for the tanks, you might have to consider placing the tanks below the ground. Above-ground tanks are typically easier to install than below-ground tanks because excavation for