Flooding is a natural and inevitable part of our weather cycle. While it will always happen in cities like Melbourne, we aim to minimise the risk to people, property and infrastructure.
Melbourne Water does this by:
- assessing the severity of flooding in various storm scenarios
- building and managing drainage infrastructure
- reviewing planning permits to ensure developments consider flood risk
- monitoring rainfall and river levels to warn other government agencies of major floods.
Why floods happen
Flooding can be caused by:
- rivers and creeks bursting their banks (riverine flooding)
- ocean tides above normal sea levels (coastal tidal and storm surge flooding)
- sea level rise resulting from climate change
However, most flooding problems happen because much of Melbourne was built following older drainage design standards. Before the 1970s, developers did not have to plan where excess floodwater would flow once the drainage system was full. This water still follows natural valleys and drainage paths — which often run through people’s properties, flooding them in severe storms.
Minimising flooding impacts
It’s impossible to prevent all floods. Extreme weather events are unpredictable, and replacing all of Melbourne’s old drains would be too costly, disruptive and time consuming — taking longer than the life of the affected buildings.
We therefore prioritise flood risks classified as extreme, based on their social, safety and economic consequences, and build infrastructure to reduce their severity and impact.
We also make sure new suburbs are better designed, with:
- underground drainage that can handle common storms
- planned overland flow paths like roads, channels and open spaces, which carry excess floodwater away from houses
Protecting yourself and your home
You can help by making sure you know the risks and are adequately prepared. Find out if you live in a flood-prone area.