This new edition of a well-established textbook covers the health, environmental, and engineering aspects of the management of rainwater and wastewater in areas of human development. Urban Drainage deals comprehensively not only with the design of new systems but also with the analysis and upgrading of existing infrastructure. Keeping its balance of principles, practice, and research, the fifth edition has had the most comprehensive update of any edition so far. It includes a new chapter on urban drainage planning, some significant restructuring of others and the introduction of new topics, including emerging contaminants, wastewater surveillance, AI, digital twins, and cyber-physical security. It also addresses current concerns about climate change impacts and intermittent wastewater pollution, and new ideas about sustainable and resilient systems. In all cases, the aim is to provide comprehensive, authoritative, and evidence-based content prioritising innovation, improved methods,