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Melbourne: Statement of Changes in Water Assets and Water Liabilities

For the water account period 1 July 2024 to 30 June 2025

  • The volume of water in the region's storages decreased by 297 GL in 2024–25.
  • This decrease represents the change in water volume in the region's surface water storages.

Schematic representation of the water flows associated with the Melbourne region's water stores, as well as the change to the region's water storage during the current reporting period.

The Statement of Changes in Water Assets and Water Liabilities provides a detailed breakdown of the actual water flows associated with the Melbourne region's water stores over the past six water accounting periods ending 30 June, as well as the changes in water assets and water liabilities that occurred during each reporting period.

To view the Statement of Changes in Water Assets and Water Liabilities, scroll down to the table below.

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 2025 (ML)2024 (ML)2023 (ML)2022 (ML)2021 (ML)2020 (ML)
Water inflows
Surface water inflows1,165,1611,421,2852,917,0641,903,8511,991,2232,345,885
Precipitation on storages55,68968,16985,52869,14270,68463,851
Precipitation on rivers11,41416,32831,23720,83117,55519,636
Flood return49,95790,868232,954128,856105,667108,303
Inflow outside region212,735212,735212,735212,735296,432214,818
Runoff811,7591,009,2002,345,0221,449,7411,407,6991,885,484
Treated wastewater discharge from urban water system*23,60723,9859,58122,54223,10416,940
Delivery received on surface water inter-region claims-- 74 70,08236,853
Urban water return*00 0000
 
Groundwater inflows547,336654,136801,743718,286684,641604,260
Inter-region coastal inflow29,64922,85128,23123,25523,54738,596
Recharge from landscape331,216399,669434,101427,256431,306334,687
Recharge from surface water*140,509189,559311,207230,982204,290205,387
Leakage from urban water system*45,96242,05728,20436,79325,49825,590
 
Urban water system inflows926,222893,066870,924859,122832,175852,922
Delivery of desalinated water004,182125,000125,000118,132
Diversion of surface water*513,533477,338451,104320,263315,125337,915
Extraction of groundwater*905181617672
Wastewater collected412,599415,677415,557413,798391,974396,803
 
Total water inflows2,638,7192,968,4874,589,7313,481,2593,508,0393,803,067
Water outflows
Surface water outflows1,557,6922,001,6443,673,8092,260,8481,967,1552,029,340
Evaporation from storages69,74570,57367,34965,05658,21357,801
Evaporation from rivers15,34019,51526,20819,89916,68115,277
Outflow680,9131,043,6202,291,3261,342,0971,139,9661,163,734
Overbank flow112,215178,903502,521259,298209,730225,989
Recharge to groundwater*140,509189,559311,207230,982204,290205,387
Allocated diversion to individual users4028,5188,3118,3118,6648,651
Allocated diversion to inter-region16,5814,5034,1783,3373,6474,263
Diversion to the urban system*513,533477,338451,104320,263315,125337,915
Non-allocated diversion to individual users8,4549,11511,60511,60510,83910,323
 
Groundwater outflows142,331148,902147,444128,104132,335202,729
Inter-region coastal outflow129,205133,292131,041111,262114,699184,378
Allocated extraction to individual users13,03615,55916,32216,78117,56018,279
Extraction to the urban system*905181617672
 
Urban water system outflows913,895888,366709,941857,813830,530837,166
Discharge to sea324,501331,243364,864326,696316,732322,703
Leakage to groundwater*45,96242,05728,20436,79325,49825,590
Other losses11,4329,9367,71618,61012,20510,023
Other wastewater losses13,32712,4578,2338,6889,05412,593
Supply of drinking water to urban customers440,050419,005255,312399,887395,871401,100
Supply of recycled water to urban customers54,85349,64636,02343,92648,06648,217
Treated wastewater discharge to surface water*23,60723,9859,58122,54223,10416,940
Urban discharge to landscape16337857100
 
Total water outflows2,613,9183,038,9124,531,1943,246,6652,930,0203,069,235
 
Unaccounted-for difference(321,695)(40,397)48,281(12,439)(354,724)(484,749)
 
 
Change in water storage      
Change in surface water storage(296,894)(110,822)106,818222,291223,002249,260
Change in groundwater storage000(6)019
Change in urban water storage000(130)293(196)
Total change in water storage(296,894)(110,822)106,818222,155223,295249,083
 
Closing water storage1,492,7321,789,6261,900,4481,793,6301,571,4751,348,180
 
 
Change in water assets claims
Surface water claims 00 148 823(68,863)(36,853)
Inter-region claims on surface water 00 148 823(68,863) (36,853)
Total change in water assets claims 00  148 823(68,863) (36,853)
 
Change in water liability
Surface water liability0000(11,229)5,271
Surface water allocation remaining: individual users0000(11,229)5,271
Surface water commitments: inter-region000000
 
Groundwater liability000000
Groundwater allocation remaining: individual users000000
Total change in water liability0000(11,229)5,271
Net change in water assets(296,894)(110,822)106,966222,978165,661206,959

* between-store flows

Note: quantification approaches used to derive each item volume are provided in the Methods