Maintaining microbial and chemical quality in Australian rainwater tanks: Insights and global advancements

The use of rainwater tanks for potable purposes is increasing across rural and urban areas in Australia, driven by the challenges of a changing climate and the associated variability in rainfall patterns. These conditions exacerbate water insecurity and leave many Australians reliant on self-sourced, unregulated drinking water supplies. However, this shift introduces significant challenges in maintaining microbial and chemical water quality. This study conducted a scoping review following the PRISMA-ScR framework to identify and address these challenges in rainwater harvesting and reuse systems in Australia. Key findings highlight the impacts of prolonged dry periods, sludge disturbance, catchment and tank materials, and insufficient maintenance practices, particularly in the aftermath of the Millennium Drought. Global advancements in rainwater collection, storage, and treatment technologies were reviewed, with actionable recommendations for application in regional Australia. Emerging opportunities include sediment management optimization and the integration of internet or artificial intelligence-based technologies to enhance tank operation and maintenance. Additionally, public education and awareness are emphasized as essential for improving water quality and public health outcomes. This study provides a pathway for advancing the resilience and efficiency of rainwater systems, supporting their sustainable use in Australia's evolving climate context.