The Black-and-White on Gray Water Recycling

28 February 2017
Posted by: Evolution
Time to read: 2 min

“Water, water everywhere and not a drop to drink.”

These Coleridge lines epitomize the paradox of an abundance of water belying the lack of potable water.  Travel through the Southern Lakes region punctuated by vast bodies of sparkling indigo fresh water makes it hard to believe that this resource is becoming scarce. 

Queenstown Lakes District Council (QLDC) explains, “A dripping tap can waste over 1,000 litres (one cubic metre) of water each day, while an average 5kg washing machine uses about 120 litres for a single wash.”  Drinking, or potable, water requires treatment and transport, and when wastage occurs, that creates a financial burden on a community.

The Superhome Movement further illustrates the situation by describing, “there is still a tremendous percentage of potable water currently being used to flush toilets, for irrigation and washing laundry,” which is unnecessary.

One solution growing in popularity is to install Gray Water Recycling in residential builds. Gray water is wastewater from showers, basins, and washing machines, diverted for garden irrigation or, if the gray water is treated, for toilet flushing.

There are various gray water systems that allow households to re-utilize water for more than one purpose in a healthy, cost-effective way.  According to Zero Energy House, two-thirds of a home's wastewater could be recycled for use in flushing toilets or watering the garden.

In New Zealand, a gray water system requires a building consent and installation has to be done by a registered plumber and drain layer. A resource consent is only required if gray water is used for irrigation. Each council within New Zealand has different rules regarding gray water recycling.

Evolution is currently installing such a system in a home being built in Queenstown’s exclusive suburb, Jack’s Point.  The homeowner aims to achieve a high Homestar™ rating of 7 or 8, and this system will contribute to that success.  The system chosen integrates seamlessly into the aesthetic design of the home, conforming to the exigent demands of this high end subdivision. 

When the region experiences water restrictions during hot dry summer spells, this home will benefit from this multi-use water system.  And the return on investment will be accelerated when the local council begins charging for water usage, which seems inevitable considering the cost to the community and the meters QLDC and other bodies have installed in recent years to monitor actual water usage and wastage.

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