Perth must more than double the amount of drinking water it supplies to its growing population by 2050 or face a shortage, according to a new report.
The city's current water supply infrastructure delivered around 300 gigalitres of water to the greater Perth area and was already reaching its limits, according to the Future Opportunities for Water Services in Perth.
However by 2050, Perth's existing water infrastructure would provide a third less drinkable water than it does currently, report co-author James Fogarty of University of WA's School of Agriculture and Resource Economics said.
Meanwhile as the Perth-Peel region's expected population grows from a current level of about two million to 3.5 million by the middle of this century, total water demand will reach 438 gigalitres per annum, consultants ACIL Allen are forecasting.
"Our analysis confirms water sources dependent on rainfall, including dams and groundwater aquifers, will continue to decline in importance," Dr Fogarty said.
"With rainfall-dependent sources falling and population rising, Perth will face a water supply challenge, requiring major upgrades to water infrastructure."
By 2050, Perth will require an additional 238 gigalitres of drinking water every year, the report said.
The cost to build new desalination plants, centralised recycling projects and associated connection and energy supply infrastructure would be in the tens of billions of dollars, sad Jeff Strahan, the managing director of privately owned water utility Water West, which commissioned the report.
Water West, which delivers local water schemes to new urban and industrial developments, is lobbying for the government to instead encourage more private-sector investment in, and allowing private utilities to build, own and operate wastewater and recycling schemes.
That would save both billions of dollars and massive amounts of valuable drinking water, Mr Strahan said.
