Perth is a city of around two million people in Western Australia. After watching its inflows reduce steadily over 40 years, Water Corporation – the water utility for Perth and most of Western Australia – embarked on an innovative program to diversify its water supply in the face of a drying climate. Now, the city relies on a resilient mix of groundwater, desalination, groundwater replenishment with purified recycled water, recycling for non-drinking, alongside a residual amount of surface water inflows. Here, we outline the journey of Perth’s water success.

By Danielle Francis, manager of policy and strategy at the Water Services Association of Australia

Perth is a beautiful coastal town in Western Australia, home to a thriving community plus mining and resources industries, agriculture, manufacturing and wineries. Traditionally it relied on dams and groundwater from the Leederville and Yarragadee aquifers. Over a 40-year period, Perth saw its rainfall reduce significantly – leading to a 50 percent reduction in stream flows into Perth’s reservoirs. The trend was so consistent that people stopped thinking of it as ‘drought’ – this was just the new normal.

With a growing population and industries, and climate change already having an impact, Water Corporation had to innovate to face these challenges. The ‘Water Forever – Whatever the Weather’ program was developed, underpinned by a strategy of ‘Security through diversity’. The program aimed to reduce water use, through water efficiency initiatives like waterwise rebates, sprinkler bans, showerhead swaps and leakage reduction programs. It also aimed to increase wastewater recycling for non-drinking uses such as irrigation of playing fields and public spaces.

A third pillar was developing new sources of water. Perth built the Perth Seawater Desalination Plant in Kwinana, which began production in 2006, and the Southern Seawater Desalination Plant at Binningup in 2011. By 2019, these plants were together producing nearly half of Perth’s water supply.

But the innovation went further. Water Corporation had been watching parts of the world, like California, that were taking water recycling a step further by treating the water to a higher level to supplement drinking water supplies. Orange County’s use of groundwater replenishment provided a model that could suit Perth. By 2008, Water Corporation gained government support for a groundwater replenishment trial at the Beenyup Wastewater Treatment Plant.

The trial took place from 2010-2012. In addition to this, over many years, Water Corporation led an extensive program of engagement with the community, the medical community, both sides of government, regulators and stakeholders. Water Corporation also created a visitor experience so that people could tour the wastewater treatment plant, learn about the advanced treatment processes, and understand the purity of the water that would be recharged into the aquifers.

The state government ultimately approved groundwater replenishment as a drinking water source, and the Groundwater Replenishment Scheme was built. The Recharge Stage 1 commenced in 2017. Stage 2, which doubled the scheme’s capacity, was completed in 2022. Perth is currently the only Australian city to be supplementing its drinking water supplies with purified recycled water. Other Australian cities are exploring this option. Over 35 cities world-wise have adopted purified recycled water in this way, with a similar number exploring it for the future.

Today, Water Corporation is preparing to deliver a new desalination plant – with Alkimos the preferred site. Other innovations continue as well. For example, in 2020, Water Corporation announced an Australian-first project to produce renewable hydrogen and graphite from wastewater in partnership with WA company Hazer Group.

With its strong history of working with the community and meet challenges head-on, the future is bright for this leader in water innovation.

Resources

• For more information about the Water Corporation, its water supply system and its programs, visit Water Corporation’s website.
• For graphs about Perth’s declining rainfall patterns and its development of a diversified portfolio, view the Water Services Association of Australia’s report on All options on the table – Urban water supply options.
• For a more detailed case study about Water Corporation’s Groundwater Replenishment Scheme, read the section starting on page 57 of the Water Services Association of Australia’s report on All options on the table – lessons from the journeys of others.
• For a photo study of the visitor centre at the Groundwater Replenishment scheme during the trial and later, view the Water Services Association of Australia’s PDF on Purified recycled water for drinking.
• For information about the 35 cities globally that have adopted purified water for drinking as part of their wastewater supply, view this PDF.
• For more information about the project that is producing renewable hydrogen and graphite from wastewater, visit Water Corporation’s website.
• To learn more about the Water Services Association of Australia’s circular economy action plan, check out the report called Transitioning the water industry with the circular economy.