Perth and the Water Challenge: A Climate-Stressed Resource

Perth's water supply has been under stress for three decades, as rainfall across the Southwest Lands division has declined measurably from the long-term average. The Gnangara Mound groundwater system, which historically supplied the majority of Perth's drinking water, has been drawn down to the point where sustainable extraction rates are significantly below past levels, requiring the Water Corporation to develop alternative sources.

The Kwinana and Southern Seawater Desalination Plants now supply approximately half of Perth's drinking water, representing the largest desalination contribution to any Australian city's water supply. The energy intensity of desalination is addressed in part through renewable energy purchase agreements, and the Water Corporation has committed to 100 percent renewable energy for its desalination operations as these agreements mature.

Water recycling for potable use has been under consideration for Perth for more than a decade. Advanced Water Treatment at the Groundwater Replenishment Scheme recharges treated water into the Gnangara Mound, building the regulatory and public acceptance framework for eventual direct potable reuse that water authorities elsewhere regard as inevitable.

Waterwise garden design has been promoted actively through Water Corporation programs that provide financial incentives for converting lawn areas to mulched native plantings. The programs have reduced household outdoor water use meaningfully, though the penetration of water-efficient landscaping across the metropolitan area remains well below the level that would materially affect system-level demand.

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