Melbourne's water storages peaked at 97% of capacity in February 2024 and fell to 63.4% on 1 June 2026, a drop of 34 percentage points. By 1 September 2026 they had recovered to 69.3%, and 2.2 points of that 5.9-point rise came from desalinated water rather than rain.
A lower inflow baseline
Average inflows to Melbourne's storages were 615 GL a year from 1913 to 1996. They fell to 376 GL a year during the Millennium Drought (1997–2009) and averaged 427 GL a year over 1997–2020. On those published averages, inflows from 2010 to 2020 came to roughly 487 GL a year, still about a fifth below the long-term level.
Wet years still happen, but do not last
In 2023-24, inflows reached 507,651 ML, 105% of the 30-year average, the year storages reached 97%. Then conditions turned. Inflows from July 2024 to June 2025 were 36% below the 30-year average, and autumn 2025 rainfall over the four major catchments was 34.8% below average in what Melbourne Water called its warmest autumn yet measured.
Desalination at full output
The state ordered 150 GL of desalinated water for 2026-27, the plant's maximum, with deliveries brought forward to June 2026. That volume is about 29% of the 509 billion liters Melbourne Water supplied in 2024-25. Melbourne's 2026 Water Outlook says restrictions may be possible over summer 2026/27 if dry conditions continue.
What sits behind the supply balance, who decides on the next source, which trunk sewers and treatment plants are being renewed, and how the A$7,307.7 million 2026–2031 capital benchmark is spread across the system are covered in the full report. The full report, Water Systems Overview: Melbourne Water, is available for USD 499 at https://ourfuturewaterintelligence.com/reports/water-systems-overview-melbourne-water. For a free overview, read the Melbourne Water Utility Snapshot at https://ourfuturewaterintelligence.com/utilities/melbourne-water.