The Adelaide Desalination Plant produced 26,176 megalitres in 2024-25, about five times the 5.3 GL annual average SA Water cites for the plant, as combined reservoir storage fell to 40% in January 2025, the lowest level in more than 25 years.
A dry year tests the backstop
Inflows to the Mount Lofty Ranges reservoirs in 2024-25 were the lowest in 40 years. The plant at Lonsdale, commissioned in 2011, can produce 100 GL a year, which SA Water says is about 50% of greater Adelaide's annual needs. In wetter months it runs in standby mode. Even in the dry year, output used only about a quarter of that capacity, leaving headroom in what SA Water calls Adelaide's only climate-independent source of drinking water.
The bill arrives through electricity
SA Water's audited accounts show electricity expense rising from A$72.4 million in 2023-24 to A$103.1 million in 2024-25, the year desalination output rose. The accounts do not say how much of that increase came from the plant, but the timing matters for customers: the revenue SA Water may recover is capped at A$5,330 million in December 2022 dollars for 2024-28.
Beyond one dry year
The River Murray supplied 44% of South Australia's water use from all sources in 2021-22, and the state's 2024 water security update projects significant drying in the southern Murray-Darling Basin by mid-century. SA Water's Resilient Water Futures work says shortfalls are possible under worst-case scenarios even with the plant fully used. In the regions, the 5.3 GL-a-year Eyre Peninsula plant is now due to deliver first water in June 2027.
How SA Water's other sources, regional systems, governance and A$3.3 billion capital program fit together, and what to watch through 2028, are set out in the full report rather than in this article. The full report, Water Systems Overview: SA Water, is available for USD 499. For a free overview, read the SA Water Utility Snapshot.