Supply
Water supply
New Zealanders use on average about 250 litres/per person/per day. However it is hard to be precise about that figure as only about 40% of our urban population is metered for water use. Metering, knowing what you use, is considered a key aspect of water use efficiency and should be encouraged, even when not required by council or when water isn’t charged for volumetrically. In Auckland where water use is measured, the average daily water use is 180 litres/per person/per day. While not high compared to the US, Canada or even Australia it is high compared to Europe and the UK. In the UK a water efficiency standard of 125 litres/per person/per day is being set for new homes in general just through water efficient appliances and fittings without the aid of supplementary supply form rainwater tanks. It’s a figure which New Zealanders could easily also achieve with a little forethought and planning and better in many areas if rainwater tanks and/or greywater recycling was used.
Design
There is never a better time to build in water efficiency than when planning a new house. Retrofitting afterwards will always be more difficult and costly. It’s a no-brainer to include the low costs items such as water efficient taps, low flow shower heads and a dual flush toilet. Even the cost of rainwater supply from an urban sized water tank is very small compared to the overall cost of a new house.
Design input from a plumber can help ensure that water efficiency is incorporated into the building. Ensure that water flow rates are specified and that product guarantees are secured. Give consideration to the following:
New Zealanders use on average about 250 litres/per person/per day. However it is hard to be precise about that figure as only about 40% of our urban population is metered for water use. Metering, knowing what you use, is considered a key aspect of water use efficiency and should be encouraged, even when not required by council or when water isn’t charged for volumetrically. In Auckland where water use is measured, the average daily water use is 180 litres/per person/per day. While not high compared to the US, Canada or even Australia it is high compared to Europe and the UK. In the UK a water efficiency standard of 125 litres/per person/per day is being set for new homes in general just through water efficient appliances and fittings without the aid of supplementary supply form rainwater tanks. It’s a figure which New Zealanders could easily also achieve with a little forethought and planning and better in many areas if rainwater tanks and/or greywater recycling was used.
Design
There is never a better time to build in water efficiency than when planning a new house. Retrofitting afterwards will always be more difficult and costly. It’s a no-brainer to include the low costs items such as water efficient taps, low flow shower heads and a dual flush toilet. Even the cost of rainwater supply from an urban sized water tank is very small compared to the overall cost of a new house.
Design input from a plumber can help ensure that water efficiency is incorporated into the building. Ensure that water flow rates are specified and that product guarantees are secured. Give consideration to the following:
- Ensure that the most water efficient products are specified, AAA or higher.
- Locate your hot water cylinder as close as possible to the point of use and get a water heater sized to family needs and insulated to prevent heat loss.
- If your local mains pressure is high consider a low pressure rather than a mains system or a pressure limiting value which reduces the pressure at the point where the water enters the property.
- Build in a supplementary supply of rainwater with a dual plumbing system.
- Consider whether a wastewater recycling system fits the situation. Wastewater recycling is particularly useful to supplement supply in parts of the country with low summer rainfall. Not all councils are supportive of wastewater recycling, mainly due to health and maintenance issues which can be overcome. However sustainable design at present includes educating and pushing boundaries where required so these type of conservation options should be well explored.
- Consider garden water needs and if in a dry area build a dripper irrigation system into the garden design. Design a garden that will only need minimal watering in summer particularly in dry areas of the country; use a concept known as xeriscaping.
- Also consider the construction of a rain garden to reduce the amount of water running off your property into the stormwater drains and if the soil and landscape requires consideration of stormwater run-off consider a rainwater tank with dual supply and stormwater detention functions.
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