Rainwater Harvesting


Pump and switching device: The main factors we considered in choosing the pump were reliability, noise and what sort of switching device. This is an elegant little device that allows us to use tank water whenever we have it and automatically switches the entire system over to town water when the tank gets low. It also includes the required backflow preventer which stops our tank water from contaminating the town water system in the event of a loss of pressure in the town supply. The one I would have liked to get was the Onga “Water Switch” because it includes a digital monitor that keeps a record of the amounts of both tank water and town water consumed. We need to know how much town water the Greeny Flat uses because the water bill is shared with the main house and we have to pay separately for the water we use. And it would be really nice to know how much tank water we use, just for interests sake. But at around $800 the Water Switch was just too expensive. So we finally settled on the Bianco “Rainsaver” which performs the same switching function but doesn’t have the monitoring capability. For around $350 we can buy two standard water meters (about $120 each) and still be well ahead of the cost of the Water Switch. As for the pump… we started out thinking that a submersible pump would be the best because they’re inside the tank and therefore quieter (theoretically, although I’ve heard varying reports about this). But one very experienced service technician told me that, over the years, he’s seen nothing but trouble with submersible pumps to the point where he doesn’t recommend them any more. Instead he suggested that an external (outside the tank) multi-stage pump would be quieter, more durable, and easier to maintain. This advice was backed-up by a number of other people I spoke to. So then I did a bunch of research into multi-stage pumps. We almost settled on the Bianco “Multi900PC” but then a tech from White Industries (who import pumps from manufacturers worldwide) suggested that, for a bit more money, the CNP CHLF2-30 would be better because the pump housing is made from cast stainless rather than stamped stainless steel which makes it quieter, more robust and more durable. Our local dealer agreed and also said that the CNP was better suited to use with drinking water than the Bianco pump. Then there was the question of who to buy it from. We could have got it a bit cheaper online but we decided to go with our local supplier, Southwell Irrigation, who have provided reliable equipment and service to my parents and their Kangaloon property to many years. They also gave us a very nice discount so the final cost for both the pump and the Rainsaver was $852.