The current fabric of urban areas is largely the result of past land development and land-use planning decisions. Historically, there was relatively little consideration of the impact of these decisions upon hydrological systems within and outside urban areas. Despite their close relationship, urban and regional planning and water resources management have typically been carried out separately and guided by different institutional arrangements. The range of impacts of urbanisation on hydrological systems at the city-region scale, and the dependence of urbanised areas upon these systems, call for better integration between the sectors of urban and regional planning and water resources management to ensure the sustainability and resilience of cities and their regions to future changes and uncertainties. This paper evaluates the extent to which planning mechanisms currently support integration between land-use and water resource sectors. The evaluation draws on a comparative analysis of 113 statutory and non-statutory planning mechanisms in three Australian capital city-regions: South East Queensland, and the Melbourne and Perth Metropolitan regions. Results indicate that the function of water at the city-region scale, including its role in supporting environmental connectivity, needs to be better understood and considered by land-use planning systems; improved institutional capacity is required to enable both sectors to deal with future changes and uncertainties related to water resources; and emergent planning trends supportive of the consideration of water connectivity at the city-region scale are yet to be fully implemented. Based on the results, the paper concludes by exploring how the concept of urban metabolism may facilitate better integration between the two sectors, along with the identification of best suited planning mechanisms and needed changes in governance and institutional arrangements conducive to integration.