1367.5 - Western Australian Statistical Indicators, 2010  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 08/04/2010  Final
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This document was added or updated on 02/12/2010.


Securing and conserving our water resources is of fundamental importance for environmental, social and economic sustainability. Drying climatic conditions and population growth in the south west of Western Australia are increasingly presenting challenges for the long term sustainability of water resources for government and the community. Nowhere is this more evident than in the capital city, Perth, where almost three quarters of the state population resides.

Current state government policies and directions for ensuring the sustainability of Western Australia's water resources are outlined in the State Water Plan 2007. One of the key objectives of the plan is water conservation and efficiency across all sectors of water use. Western Australian households currently represent an important sector of water use and are likely to remain so in the future. According to the WA Water Corporation's most recent figures, 71% of Perth's scheme water usage is residential.

Water Forever, is the Water Corporation's strategy for delivering a sustainable water supply to Perth over the next 50 years. One of the main objectives of the plan is a 15% reduction in household and business water use by 2030 (and 25% by 2060) to ensure water supply can meet the future demand for Perth and surrounding areas. More efficient use of water by households will be a key factor in achieving this target as will be the increased use of recycled water.

This article examines a range of factors impacting on water usage in Perth households in 2009, including household sources of water and the uptake of water-saving devices in the home and garden. The article draws primarily on data from the 2009 Survey of Household Choices Related to Water and Energy and compares water choices according to household size, tenure type, income and relative disadvantage of areas within the Perth Statistical Division. Information from other sources, including an ABS national survey on Environmental Views and Behaviour provide context and background.


In 2007-08, the Environmental Views and Behaviour Survey found that almost nine in ten adults aged 18 years or over in Perth were concerned about water shortages while three out of four adults were concerned about climate change. However, only 40% of adults in Perth indicated that they had decreased their personal water use in the 12 months prior to the survey. Just over half (51%) of all adults stated that their water use had remained the same while for 8% it had increased. A lower proportion of people in Perth than in most other state capital cities in Australia reported that they reduced their personal water use. The stricter water restrictions operating in New South Wales, Victoria and South Australia at the time of the survey are one likely contributor to this difference.

Decreased Personal Water Use in the Previous Year, 2007-08
Graph: Decreased Personal Water Use in Previous Year, 2007-08

In 2007-08, those survey respondents who reported a decrease in their personal water use were asked to identify reasons for the decrease. Some survey respondents cited more than one reason. Four out of five adults (80%) in Perth indicated that they had actively tried to conserve water at home. One in four said that the tightening of water restrictions was a reason for reducing personal water use. However, people in Perth were less likely to cite water restrictions as a reason than people in other city locations (25% compared with 46% nationally).

Reasons Given for Reducing Personal Water Use 2007-08(a)

Graph: Reasons given for Reducing Personal Water Use - 2007-08

Of those who had increased their personal water use, a lifestyle change (42%) was the most common reason given, followed by increased water needs in the garden (26%).


The average 'wet season' rainfall in the south west of Western Australia has declined by 10% since the mid 1970s, resulting in a 50% reduction in the stream flows into Perth dams over the past 40 years (CSIRO & Bureau of Meteorology). As a consequence of lower stream flows into the dams, Perth has drawn increasingly from other sources of water in recent years. In 2008-09, half (50%) of Perth's scheme water came from ground water resources while one third (35%) was supplied from surface water (dams). The Perth sea water desalinisation plant in Kwinana, which was commissioned by the Water Corporation in 2006, provided 13% of Perth's scheme water.

Sources of Water, Perth

Graph: Sources of Water, Perth

The Integrated Water Supply Scheme (IWSS) operated by the Water Corporation delivers most of the water in the Perth metropolitan region. In 2008-09 the volume of scheme water supplied to Perth by the IWSS was 264,352 megalitres, 4.5% more than was supplied in the previous year and 8% more than in 2004-05. In 2008-09, two thirds (66%), or 174,401 gigalitres, of this water was supplied to residential properties, an increase of 5% compared with the previous year and 8% more than in 2004-05. This increase in use must be seen in the context of a growing population. Since 2004-05, the number of residential properties and population accessing the IWSS have increased by 12% and 13% respectively.

Water for the IWSS comes from three sources:

Surface water is obtained from dams (storage reservoirs) in the Darling Range. Surface water sources supply between 25% and 45% of the water for the IWSS. The dams supplying water are Canning, Serpentine Pipehead, Conjurunup Pipehead, Victoria, Mundaring Weir, South Dandalup, North Dandalup, Wungong, Stirling and Churchman's Brook.  Note that Mundaring Weir normally only supplies water to the Goldfields and Agricultural Region.

Groundwater, supplying 35-50% through the integrated system, is obtained from natural reservoirs in the deep sands of the coastal plain. It is treated at groundwater treatment plants at Jandakot, Mirrabooka, Wanneroo, Neerabup, Lexia and Gwelup before being added to the distribution system. The largest aquifer to support Perth's water supply is the Gnangara Mound (located north of Perth); it currently supplies about 60% of total groundwater.

The Perth Seawater Desalination Plant in Kwinana supplies 15-20% of water needs. The largest desalination plant in the southern and eastern hemispheres; it produces on average 130 million litres of water a day.

Source: Water Corporation

Household Sources

In 2009, almost all (98%) households in Perth were connected to mains water. Mains water provides scheme water of a quality fit for drinking. Rainwater tanks and garden bores can provide an alternative source of water for households, particularly for gardens, lawns and outside use, thereby relieving pressure on mains water supply. In 2009, less than 8% of Perth households had a rainwater tank, compared with 28% in the balance of WA. One quarter (25%) of Perth households surveyed in the 2009 Survey of Household Choices Related to Water and Energy reported that they had access to a garden bore, a higher proportion than in other areas of the state (13%).

If used responsibly, and located away from the ocean, river systems and wetlands, garden bores can be a suitable supply of water for outdoor use (State Water Plan 2007). The Water Corporation supports increased monitoring and reporting on this resource to ensure its long term sustainability. As would be expected, households in separate dwellings were more likely than those in other dwelling types to have access to these alternative water sources.

Household Water Supply, 2009
Graph: Household Water Supply, 2009

Water Saving Facilities

About half of household water use is inside the home. (For more detailed information see the Water Corporation's Perth Residential Water Use Study, 2008-09.) The use of more water efficient appliances combined with behaviour change around the home can greatly reduce this water consumption. To stimulate the uptake of water efficient fixtures and appliances and to drive market innovation, the state government introduced a rebate scheme in 2003 which ran for six years. The Commonwealth Water Efficiency Labelling and Standards Scheme (WELS), introduced in 2006, required a water using fixture or fitting to be rated for its water efficiency. From July 2006, the products legally required to have a WELS rating include shower heads, tap equipment, toilet and urinal equipment, clothes washing machines and dishwashers. Furthermore, all new homes and major renovations in WA are now required to meet minimum 'Five Star' water efficiency standards.

The proportion of Perth households having more water efficient toilets, shower heads and washing machines has increased over the past few years. Between 2006 and 2009, the proportion of dwellings in Perth with at least one dual flush toilet increased from 84% to 91%, while those with at least one low flow shower head increased from 51% to 60%.The proportion of dwellings with front loading washing machines grew from 25% to 34% over the same period.

Water Saving Facilities in Perth Households

Graph: Water Saving Facilities in Perth Households


The presence of water saving devices in the home varied by household type. In general, households with higher incomes, in separate houses and owner-occupied dwellings were more likely to have water efficient fixtures and appliances in the home than other household types. For example, dwellings that were fully owned or being purchased were more likely to have at least one low flow shower (66%) than rental dwellings (46%). Similarly, low flow showers were more likely to be present in separate houses (64%) than in other dwelling types (49%). Almost half (47%) of Perth households with an annual income greater than $110,000 per year had a front loading washing machine, compared with 20% of those with an annual income of less than $25,000.

The presence of water saving fixtures and appliances also increased with household size. Households with three or more people were more likely to have at least one low flow shower and a front loading washing machine than single person households.

With around half of household water use in Perth occurring outside the home, dwelling type can have a major impact on household water use. Multiple dwellings (terrace houses, townhouses or apartments) are likely to have smaller living areas, smaller gardens (or no garden) and therefore lower water consumption. The 2009 Survey of Household Choices Related to Water and Energy found that over three-quarters (78%) of Perth households lived in detached dwellings (separate houses) and almost all of these homes (98%) had a garden and/or lawn. By comparison, less than half (41%) of households occupying other housing types had gardens or lawns.

Household Water Characteristics, Perth - 2009

Household type
At least one dual flush toilet
At least one low flow shower
Front loader
Has garden or lawn
Has access to bore
All households


Dwelling Type
    Separate house
    Other dwelling type (a)
 Tenure (b)
     Fully owned/being purchased
Household Size
    One person
    Two person
    Three or more persons
 Household Income (c)
    Less than $25 000
    $25 000 to less than $50 000
    $50 000 to less than $70 000
    $70 000 to less than
    $110 000
    $110 000 or more
All households ('000)

(a) Includes categories semi-detached, row or terrace house, townhouse etc. Flat, unit or apartment and other housing types.
(b) Excludes other.
(c) Excludes don't know/refusal.
Source: Household Choices Related to Water and Energy, WA, October 2009 (cat. no. 4656.5)

Households Receiving Concessions on Water Charges

The Water Corporation offers rebates to eligible pensioners and seniors to help maintain affordability of water services. Holders of a WA Seniors Card, a Commonwealth Seniors Health Card, a Pensioner or State Concession Card, may receive rebates on their annual water service charges. Of the estimated 179,800 households in Perth that received some form of concession on water bills, 13% had single flush toilets only in their home. The remaining 87% had at least one dual flush toilet. Of the households receiving concessions, 57% had at least one low flow shower head.

Households not receiving concessions were more likely to have water efficient toilets and showers installed. The proportion with single flush toilets only, therefore, dropped to 8%, while 92% had at least one dual flush toilet. Likewise, the proportion with low flow shower head attachments was higher (62%) in households not receiving concessions.

Water Saving Facilities, Households with and without Concession Cards, Perth - 2009

Graph: Water Saving Facilities, Households with and without Concession Cards, Perth - 2009


As indicated above, water choices tend to vary with household size, tenure type and dwelling type. As part of this analysis, the relative socio-economic disadvantage of the area in which the household was located was also investigated.

The following analysis examines water choices in Perth homes in terms of the Index of Relative Socio-Economic Disadvantage (IRSD), one of four Socio-economic Indexes for Areas (SEIFA) developed by the ABS. It should be noted that the SEIFA ranking attaches to areas, not to persons, households or dwellings. It provides a summary of the socio-economic characteristics of an area. In particular, the IRSD ranking represents the relative level of socio-economic disadvantage in the area in which a person lives.

Index of Relative Socio-Economic Disadvantage (IRSD)

The ABS has developed four Socio-Economic Indexes for Areas (SEIFA) to rank the level of social and economic well-being of a region. The SEIFA indexes are created by combining information collected in the five-yearly Census of Population and Housing. The Index of Relative Socio-economic Disadvantage (IRSD), used in this article, combines 17 variables from the 2006 Census (including income, education and unemployment) relating to the people, families and dwellings within each area; and ranks these areas on a scale of relative disadvantage. For the purposes of the investigation, all areas within Western Australia were ordered into quintiles according to their IRSD score. The first quintile (the lowest 20%) represents the areas of greatest relative disadvantage and the fifth quintile (the highest 20% ) represents the areas of least relative disadvantage.

The map attached to this article (Attachment 1) shows the IRSD for census collection districts (CCDs) within the Perth region. At the time of the 2006 Census, the CCD was the smallest geographic area in the Australian Standard Geographic Classification (ASGC), with an average of 225 dwellings per CCD.

For more information on SEIFA see Information Paper: An Introduction to Socio-Economic Indexes for Areas (SEIFA) 2006 (ABS cat. no. 2039)

In general, households located in more disadvantaged areas of Perth were more likely to be renting and contain fewer people. They were also more likely not to be living in a separate house and to be receiving concessions on their water bills. Households in the areas with the greatest relative disadvantage (lowest quintile) were most likely to have these attributes. In contrast home ownership rates, household size and the number of people in the dwelling increased for households in areas that were less disadvantaged.

Water Saving Devices by Disadvantage

While there was no discernible pattern in the relative disadvantage of an area and the proportion of households with dual flush toilets or low-flow showers, there was a noticeable pattern in the proportion of households with front loading washing machines. This proportion decreased with the relative disadvantage of the area. Only one-quarter (24%) of households in the lowest quintile had a front-loading washing machine, compared with 42% of those in the highest quintile.

Households with Front Loading Washing Machines, Perth, 2009

Graph: Perth Households with Front Loading Washing Machine, 2009s,

Gardens and lawns by relative disadvantage

In 2009, households in the lowest IRSD quintile were least likely to live in a dwelling with a garden or lawn, reflecting their lower propensity to live in a separate house as opposed to a higher density dwelling.

Perth Households, by Relative Socio-economic Disadvantage of Area, 2009

Graph: Perth Households by Relative Socio-Economic Disadvantage of Area, 2009


In recent years, there has been growing community concern about the diminishing supply of water in Perth dams, the associated rising cost of water to consumers and the tightening of restrictions on the use of mains water in metropolitan gardens. Although a significant proportion of residents in the Perth metropolitan region reported a reduction in their water use in 2007-08, a 12% rise in the population over the last five years has been accompanied by a rise of approximately 8% in total residential scheme water use.

Between 2006 and 2009, there was a significant increase in the uptake of water efficient fixtures and appliances in Perth homes, particularly low flow showers, dual flush toilets and front loading washing machines. In general, uptake of these devices was greater for households in detached (separate) dwellings; in owner-occupied dwellings; and households with three or more people. Uptake was greater also in households with higher incomes and those not receiving any concessions for their water services.

Such households were more likely to have access to water efficient fixtures and appliances inside the home than other household types; for example, renters, persons living alone, households with low incomes, and those in higher density housing. However, households with access to water efficient fixtures and appliances within the home were also more likely to have lawns and gardens, currently responsible for around half of all domestic scheme water usage. These findings suggest that, in the face of continuing low rainfall and a rapidly growing population, an understanding of the water choices made by different households will be needed to inform policy on ensuring a sustainable water supply for Perth.

Map: Index of Relative Socio-Economic Disadvantage, Collection District Quintiles, Perth Statistical Division


Household Choices Related to Water and Energy , WA, October 2009, ABS cat. no. 4656.5.

Environmental Views and Behaviour, 2007-08 , ABS cat. no. 4626.0.55.001.

Information Paper: An Introduction to Socio-Economic Indexes for Areas (SEIFA) 2006, ABS cat. no. 2039.0.


CSIRO & Bureau of Meteorology, Climate change in Australia: technical report 2007, http://www.climatechangeinaustralia.gov.au/technical_report.php.

Department of Premier and Cabinet, State Water Plan 2007, http://www.water.wa.gov.au/State%20Water%20Plan%202007.pdf?id=31

National Water Commission April 2010, National Performance Report, 2008-09: urban water utilities,http://www.nwc.gov.au/www/html/2765-national-performance-report-2008-09---urban-water-utilities.asp

Water Corporation, http://www.watercorporation.com.au.

Water Corporation, Water Forever: Towards Climate Resilience, October 2009, http://www.thinking50.com.au/files/Water_Forever_-_Towards_Climate_Resilience_(web).pdf

Water Corporation, Perth Residential Water Use Study 2008/09, http://www.thinking50.com.au/.