Water And Sustainable Design

Water is fast becoming a scarce resource. Climate change, water pollution and increasing urban and rural demand for quality water is draining natural fresh water resources. As part of eco-friendly building and sustainable energy programs, water conservation and management measures are being integrated into home design and adopted throughout the construction process.

The aim of sustainable water management is to reduce, reuse and recycle domestic water use, thereby contributing savings in energy and water. In turn, this reduces the environmental impact of both transporting water and water disposal over long distances. Such strategies positively impact carbon emissions, with the hope of curtailing the climate change, and the treat of impending water shortages.

Sustainable water management strategies include:

• Water Conservation
• Water Tanks
• Water-efficient Appliances

Water Conservation

Water conservation in homes requires effective plumbing design. This includes:

• A gravity hot-water system - lower water pressure results in less water usage than a mains pressure hot-water system.
• Point of use water heaters - avoids wasting cold water while waiting for hot water to reach the taps.
• Well-lagged and positioned pipes - helps to keep water hot. A
• Water-efficient appliances and fittings

Water Tanks Systems

Water tank systems are used to collect and filter grey water from sinks and laundries, for use in toilets and irrigation. This is known as greywater recycling.

Water can be collected from roofs can be recycled for flushing toilets, filling washing machines and watering gardens.

Greywater from baths, sinks and showers and can be recycled and reused for watering the garden or flushing toilets. This can save up to 50% of domestic water use. Used on the garden, greywater requires no treatment. However, greywater used for domestic purposes requires some form filtering and disinfectant to remove bacteria and other biological material.

Greywater systems require the household use only biodegradable, non-toxic household cleaning and toiletry products. Fats and additives are not suitable for even garden usage. Soils should be test regularly to ensure toxicity or ph issues do not arise.

Stormwater Systems

Urban stormwater systems capture rainwater from streets, carparks and roofs and channel it into waterways and estuaries. Along with it pollutants and rubbish enter our natural water sources.

Urban infill has increased the relative area of impervious hard surfaces leading to erosion, flooding and damage to ecosystems.

Both these problems can be reduced with improved design of drainage and stormwater systems which use filters and detention systems. Detention systems harvest rainwater for local recycle, whilst reducing stormwater run off.

Water Efficient Fittings

Use of water efficient plumbing fittings can reduce the use of water in the home by as much 30%. This includes:

• Low water shower fittings
• Sensor controlled taps
• Dual flush toilet cisterns - providing low flush and standard flush
• Displacement devices in toilet cisterns
• Waterless urinals, pressure assisted toilets and dry composting toilets

Most plumbing fittings today must compy with water efficiency ratings. Labelling for products defines this rating against the national standard.

Hot water pipe work should always be lagged with insulated, ecofriendly lagging to reduce the water flow before hot water reaches the taps.

Taps and Fittings - account for around 8% of domestic water use. Tap design impacts water usage:

• Conventional twist taps - use around 4 litres per hand wash
• Water efficient fixtures - use only 2 litres or less.
• Push taps and sensor taps [self-closing]
• Spray taps - reduce flow volume
• Flow regulators and restrictors - restrict flow, regulate pressure and reduce the force to turn the flow off.

Showers - account for around 20% of domestic water use. Showers should be more water-efficient than baths, however the popularity of modern power showers significantly increases the water usage in a shower. The choice of showerhead can halve water usage:

• Regular showerheads - use around 20 litres per minute
• Low-flow showerheads - use less than 10 litres per minute by creating finer drops or using pressure powered aeration.

Water Efficient Appliances

Dishwashers - high efficiency dishwashers save both water and energy. Water efficient dishwashers use only 16 litres of water per load compared to 40 litres for hand washing dishes.

Washing Machines - account for about 14% of domestic water use. Modern high efficiency models use less than 50 litres per load, compared to over 100 litres by older models. NOTE: A full load is always more water efficient than a half-load. Look for water usage rates on the energy label. The most efficient machines are rated G, the least A.

Eco-friendly Considerations

Pipe work insulation - ensure manufactured materials are both CFC and HCFC free. Pipe lagging manufactured from recycled wool scrap is also available.

PVC - is hotly debated as to its environmental suitability. There are a number of alternatives to PVC pipe work systems.

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