Regional households in Western Australia are doing more than metropolitan Perth residents to reduce water usage in a drying climate, government statistics have shown.
According to the Economic Regulation Authority (ERA) annual Water, Sewerage and Irrigation Performance report, the average regional household used 7.2 per cent less water in 2015-16 than the previous year, while the average Perth household used 1.6 per cent less.
The report reviewed the Water Corporation’s performance in 42 towns and cities across the starte where more than 1000 properties are connected to a water supply.
In 2015-16 it included 34 regional schemes with between 1000 and 10,000 connected properties, 11 more than previous years, and allowing for the merger of the Port Hedland and South Hedland schemes into one Hedland scheme.
The report found, average annual residential water supplied in regional towns continued a long-term downward trend in 2015-16 due to water savings measures across the state.
In 2015-16, Wickham had the highest average annual residential water consumption at 550 kilolitres per property, followed by Kununurra at 481kL/property.
Lancelin had the lowest average annual residential water consumption at 104kL/property.
Groundwater drawn from aquifers was the main source of water for regional towns, comprising 63.8 per cent of the total supply, the highest level in the past six years.
Groundwater and bulk water – from a utility or entity other than Water Corporation – has replaced surface water from dams, rivers and irrigation channels in the past six years, the report stated.
It found overall, water drawn from WA’s dams, rivers and irrigation channels had fallen by 75 per cent in six years.
Perth’s reliance on water sourced from the Binningup and Cockburn Sound desalination plants increased by 13.8 per cent in 2015-16, overtaking groundwater as a source for the first time.
ERA chairwoman Nicky Cusworth, said reduced reliance on rainfall dependent surface water to provide drinking water for regional towns and metropolitan Perth was a result of government strategy to accommodate a changing climate..
“This is the result of the Water Corporation’s strategy to source more water from sources independent of climate,” Ms Cusworth said.
“The long-term upward trend in Perth’s water supply is being driven by population growth and the consequential residential property development.
“On average in the regions, water supplied to residential properties continued its long-term downward trend.”
Regional towns were taking on water saving measures with average annual residential consumption at its lowest levels in six years, Ms Cusworth said.
Some of the savings came from increased use of recycled water for uses other than drinking water.
The largest use of recycled water, the report indicated, was in the commercial, municipal and industrial sector with 53.9 per cent, followed by agriculture at 23.6 per cent and on-site reuse 14 per cent.
The report also covered the state’s two largest irrigation schemes regulated by the ERA, the Ord Irrigation Co-operative, trading as Ord Irrigation, and the South West Irrigation Management Co-operative, trading as Harvey Water.
Water volume supplied by Ord Irrigation decreased 8.8 per cent in 2015-16 to 133,699 megalitres.
Despite the drop, the supplied volume was still much higher than volumes supplied in the four years before a 2014-15 spike, the report indicated.
The volume supplied by Harvey Water increased by 2 per cent in 2015-16 to 53,456mL.
Prior to 2013-14, the volume supplied had been trending down because of reductions in Harvey Water’s water allocations due to dry weather and a contraction in the local dairy industry, the report stated.
A higher water allocation in 2013-14 reversed the trend, but the gains of 2013-14 had not continued into 2014-15 and 2015-16, it stated.
The number of connection points on the Harvey Water network declined 1.1 per cent in 2015-16.
According to the report, the number of sewerage connected properties in Perth and regional towns increased, by 3.1 per cent and 13.8 per cent respectively.
Excluding increases attributable to the 11 new towns connected, the average volume of sewage collected per property was 173.4kL in 2015-16, which was 2.3 per cent lower than 2014-15.
Kununurra had the highest volume of sewage collected per property at 231kL, followed by Wickham, 229kL, and Harvey-Wokalup, 216kL.
Exmouth with 73kL per property had the least collected.
On numbers of billing and account complaints related to water and sewerage charges, the report stated Kalbarri recorded the highest with 1.2 complaints per 1000 connected properties, followed by Bunbury with 1.1 per 1000 properties.
There were 27 regional towns that did not record any billing and account complaints in 2015-16.