Sustainable water systems often comprise complex combinations of traditional and new system components that mimic natural processes. These green systems aim to protect public health and safety, and restore natural and human landscapes. Green infrastructure elements such as most sustainable drainage systems trap storm water but may contaminate groundwater. There is a need to summarize recent trends in sustainable water systems management in a focused document. The aim of this special issue is therefore to disseminate and share scientific findings on novel sustainable water systems addressing recent problems and opportunities. This special issue focuses on the following key topics: climate change adaptation and vulnerability assessment of water resources systems; holistic water management; carbon credits; potable water savings; sustainable water technologies; nutrient management; holistic storm water reuse; water and wastewater infrastructure planning; ecological status of watercourses defined by the Water Framework Directive. The combined knowledge output advances the understanding of sustainable water, wastewater and storm water systems in the developed and developing world. The research highlights the need for integrated decision-support frameworks addressing the impact of climate change on local and national water resources management strategies involving all relevant stakeholders at all levels.