This discussion paper explores the marketisation of fresh water through a discussion of water trading and water markets in Australia. It describes the rise of water licensing as a central measure in water management and the implications of this for the further commodification of fresh water. This occurs in the context of systematic and ongoing over-allocation and over-extraction of fresh water from the Murray-Darling Basin. These trends and issues pose major problems for future water security and sustainability, particularly insofar as they are linked to the degradation and depletion of water basins and the loss of biodiversity in the Basin.