RÉSUMÉ
It is widely accepted that new, more sustainable approaches to urban water management are required if cities and ecosystems are to become resilient to the effects of growing urban populations and global warming. Climate change predictions show that it is likely that cities around the world will be subject to an increasing number of extreme and less predictable events including flooding and drought. Historical transition studies have shown that major events such as extremes can expedite the adoption of new practices by destabilising existing management regimes and opening up new windows of opportunity for change. Yet, they can also act to reinforce and further entrench old practices. This case study of two Australian cities responding to extreme water scarcity reveals that being unprepared for extremes can undermine progress towards sustainable outcomes. The results showed that despite evidence of significant progress towards sustainable urban water management in Brisbane and Melbourne, the extreme water scarcity acted to reinforce traditional practices at the expense of emerging sustainability niches. Drawing upon empirical research and transitions literature, recommendations are provided for developing institutional mechanisms that are able to respond proactively to extreme events and be a catalyst for SUWM when such opportunities for change arise.