Warragamba Dam is at full capacity
24 MAY 2025Following recent rainfall across Sydney's water supply catchments, Warragamba Dam reached full capacity at 5pm and a small spill may commence later tonight. Based on current inflow predictions, the peak outflow could be around 20 gigalitres a day (GL/d) on Sunday morning 25 May.
Residents are reminded to remain alert to warnings. If you are downstream of the dam, stay away from fast flowing or deep water near waterways and floodplains.
Most other smaller Greater Sydney dams are currently spilling, including Woronora, Nepean, Cataract, Avon and Tallowa.
WaterNSW continues to work with the Bureau of Meteorology and SES to monitor the weather event.
The community should continue to monitor advice on river levels and any flood warnings from the Bureau of Meteorology.
- For the latest weather and flood information, check the Bureau website – bom.gov.au/
- For emergency information, contact the NSW SES – 132 500 or ses.nsw.gov.au
Background
Spills from Warragamba Dam are not uncommon, occurring more than 50 times since 1960. In 2024 the dam has spilled on 5 April (peak spill rate 220GL/day), 6 May (peak spill rate 30GL/day), and 7 June (peak spill rate 240GL/day),
The Warragamba Dam catchment area covers 9000 sq/km and stretches across much of the Blue Mountains to Goulburn in the south, and to Lithgow in the north.
As manager of the state’s major supply dams, WaterNSW operates Warragamba Dam in line with NSW Government operating rules and regulations.
These rules do not permit water being released to reduce the storage level ahead of predicted rainfall for flood mitigation purposes. This reflects the dam’s critical role in supplying 80% of Sydney’s drinking water.
For operational reasons, access to the Warragamba Dam wall and Terrace Gardens is unavailable on 24 and 25 May 2025. The picnic areas and facilities remain available to visitors, and the Eighteenth Street viewing platform will remain open.
Background – dam operations
During times of flood, the gates on Warragamba Dam automatically open and close based on water levels.
After rainfall has occurred and when the water rises above full supply level, the gates progressively open in sequence. As water levels begin to drop, the gates will progressively close in reverse sequence.