Timber water tank for rainwater harvesting at Kerikeri

Timber water tank for rainwater harvesting at Kerikeri

Why don’t more Kiwis don’t invest in economical rainwater harvesting systems?

Friday, 24 February 2012

Why don’t more Kiwis don’t invest in economical rainwater harvesting systems for their home or business properties? This question is posed by Justin Jordan of Timbertank Enterprises.

"The public and industry want to harvest rain water as being good for the environment and to save money, and industrial concerns are also keen to reduce waste water consents and costs," he says. "However, most Councils do not see why the public should harvest rain water when town supply is so cheap.

"The public needs more guidance from Councils as to the volume of storage they are happy with, so responding to public keenness to harvest rain water. It's a disgrace that over 50% of potable water in New Zealand is flushed down the loo", he says. "We simply can't afford to keep on this slippery path.

"Currently Councils feel the burden on water stocks when we have a dry spell - small tanks run out and people switch to town supply, when town supply is running short too. It's a double whammy. So we need to slow this water cycle down.

"In dry summers, people are calling out for rain, then when it comes, they don't conserve it. But if people had at least a 20m3 tank at home, or a decent installation - say 100m3 - at their industrial site, there would be a huge saving of a precious resource."

The key question to be answered is, how much water storage is enough? And that depends on the needs of the water user. Enquiries from industrial concerns who want to become better 'green' users and cut down on their water use - particular wastewater, are resulting in Timbertanks increasingly providing effective rainwater harvesting systems to reduce use of Council provided water.

"We have developed a system using downpipe surge collection to divert rainwater from different shaped roofs into holding tanks, which are then piped to be used for flushing lavatories etc.

"We have recently done two major installations in Auckland - one at the Auckland Prison in Mt Eden, with two x 100m3 holding tanks, the other at Auckland Domestic Airport, with a 70m3 tank."

Part of the investment problem is having economical systems available. Justin says costs vary according to the size of the installation, but a typical downpipe connection is estimated at $600, plus the cost of the holding timber tank and plumbing. For a standard 20m3, 3.5m diameter tank for home use, cost would be in the vicinity of $12 - 15,000. The company is also able to offer elevated gazebos over water tanks as an attractive garden asset.

"More rain falls than you could ever use, so the key to the success and the payback is to install the biggest tank you can afford," says Justin. "I believe that flushing your loo with premium drinking water is almost criminal! Why not save the environment and money at the same time?

"Depending on the installation, a water bill can reduce by at least 40% and up to 60% in some cases - payback is 5-7 years. It is particularly cost effective for industrial situations. And for industrials we would expect their use to grow, so Timbertank systems are planned to allow tanks to be rebuilt to a larger size, for a small cost."

The photo shows a different approach to utilising a rainwater harvesting tank at the Kerikeri Riding School. A viewing platform/gazebo has been erected overlooking the equestrian dressage arena on the newly constructed 45m3 Timbertank. Water is collected from the roof of the adjacent indoor arena and piped to the tank.