the most arid inhabited continent, can provide only a limited amount
of fresh water. As our population grows, so too do the rates of water
extraction and pollution. To
supplies of fresh, clean water we must start to think more carefully
about how we use it.
building design can
greatly reduce the amount of water we use and the degree of
contamination we cause. The following methods show you how to use
water in a sustainable way.
of each of these will depend on whether you live in the city or the
country, in the tropics or the warm temperate south. Examine the
options presented and decide which design solutions would improve
your quality of life and reduce your impact on the environment.
REDUCING WATER DEMAND
toilets and showers are
key areas where water consumption can be reduced by installing
appropriate fittings. Simple changes can reduce the pressure on
reticulated water supplies and reduce your water bills. Fit
AAA rated showerheads. Replace
toilet cistern with a 6 litre/3 litre dual flush cistern if you don't
already have one. This usually requires changing the toilet bowl as
well, since the 6/3 dual flush requires a differently shaped bowl. Fix
environmental benefits include:
Lower water use.
Decreased sewage volume.
appropriate taps. Mixer
taps in showers can reduce the potential for scalding and save large
quantities of hot water. But because mixer taps over basins and sinks
are often left in the middle position, most models waste hot water.
Separate hot and cold taps are preferred in these situations.
RAINWATER COLLECTION AND
provide a useful sole or supplementary water supply in most regions
of Australia. These systems are especially recommended in areas where
water supplies are limited. Rainwater
be used for drinking or for watering the garden. Drinking rainwater
is not a health risk in most areas of Australia, providing the system
ON SITE WATER REUSE
appropriate treatment, and
if local regulations allow wastewater can be used to flush toilets,
water the garden and even to wash clothes. Greywater
wastewater which does not contain human excreta. Blackwateris
wastewater containing human excreta. Blackwater is sometimes mixed
with greywater but there are distinct advantages in keeping grey and
for greywater, blackwater and combined wastewater use are discussed
in detail in this fact sheet. Methods of use include:
Greywater for garden use
and toilet flushing.
Septic tank systems for
black and greywater.
treatment systems (AWTS).
Reed beds and sand filters.
Wet and dry composting
disinfection systems are
also discussed, including:
Active and passive
Wet weather storage
Soil purification, carbon
most appropriate choice of system depends on:
Where you live, your soil
How much space you have.
Whether you are connected
to the sewer.
How much water you use.
What you put down your
'dry sanitation' systems do not use water to treat or transport human
excreta. If appropriately designed and operated they conserve
precious water resources and avoid disposing of effluent and
pollutants into waterways and the wider environment.
best way to
simplify wastewater treatment is to avoid mixing it with human
excreta. Blackwater is the most difficult form of wastewater to treat
due to the presence of pathogens.
the term given to pure rainwater, plus anything the flowing rainwater
carries along with it. Avoid
cut and fill on
your block when preparing the building foundations. Attempt to
maintain the existing topography and drainage pattern. If you do have
to cut and fill, stabilise the soil and revegetate as soon as
deep-rooted trees that can lower the water table, bind the soil,
filter nutrients, decrease run-off velocities, capture sediment and
reduce the potential for dryland salinity. Retain
your block with permeable paving, pebble paths, infiltration
trenches, soakwells, lawn, garden areas and swales. Minimise
surfaces such as paved areas, roofs and concrete driveways.
OUTDOOR WATER USE
to 60% of
household water is used outdoors. Using water conservation techniques
in the garden will ultimately save you money, time and effort. Minimise
lawn areas. In
most gardens, lawns consume up to 90 percent of outdoor water and
most of the energy used outdoors. To reduce outdoor water use replace
lawns with groundcover plants or mulched garden beds. Mulching
plants conserves water by preventing evaporation and reducing
drought tolerant species. Australian
natives, succulents, cacti, olive trees and some exotic ornamentals
are suitable. Improve
addition of organic matter, gypsum, sand and other compounds can
improve soil condition, water retention and drainage. Hardy,
deep-rooted plants can help break up poor soils.