In the Australian context integrated urban water management (IUWM) processes consistently recommend the implementation of recycled water and stormwater harvesting projects. These projects are typically decentralised and planned by a variety of organisational types. Major international research programmes have thus far focused on how IUWM should be operationalised as a single-tier, city scale planning system. This study investigates IUWM in relation to two under researched aspects: planning scales and approval processes, by investigating eight project case studies from Melbourne, Australia. Results reveal that IUWM projects are often planned at the sub-regional and local scales, without coordination from metro scale strategies, and that many of these projects are experiencing issues achieving final approvals. Major barriers to approval include a lack of communication between regulators and planners, and the absence of consistent financial evaluation methods. A multi-tier water planning system has been proposed to lessen these barriers through effective division of decision making responsibilities across scales, and setting of consistent frameworks, methods, and objectives at the metro scale. It is considered that this multi-tier planning system may help facilitate the implementation of decentralised IUWM projects.