To better meet the challenge of managing our freshwater resources from pressures such as population growth, extreme events, climate change and industry impacts, we require a step change in monitoring and forecasting capabilities to provide management-ready information at scale across wider geographical areas. To meet the resource challenges we face, we should exploit diverse and integrated approaches, from traditional sampling, in situ sensors, satellite observations and advanced modelling. The AquaWatch Australia Mission, proposes such a step change in monitoring technologies to support the scales and speeds at which models now operate and to safeguard water bodies. The concept proposes an integrated nationwide ground-to-space national monitoring platform incorporating satellite and in situ sensor observations together with a dedicated data analysis platform to address stakeholders needs. Key characteristics required for a nationwide in situ water quality monitoring sensor network include: a) cost-effectiveness to both construct and operate; b) maintainability, and; c) timely, robust and credible data to integrate with other data sources to address decision making needs. An Internet of Things (IoT) solution is perhaps seen as the most cost-effective approach to deliver ubiquitous and autonomous sensing across wide spatial and temporal scales, but to date the research only highlights localised examples. Similarly, reliable and cheap water quality sensors suitable for IoT adoption remain largely in the research domain. New sensors will also need to be innovatively and robustly constructed for IoT systems characterised by resource constraints: in communication capabilities, energy, processing capabilities and limited data storage. The paper will and address the challenges we face in: 1) the development of nationwide water quality networks for improved management of freshwater resources. 2) the new thinking required to cost-effectively address water quality parameter detection and, 3) the challenge to integrate and analyse real-time data generated from a highly distributed and heterogenous sensor networks.