Understanding the impacts of urbanization on the urban water cycle and managing the associated health risks demand adequate strategies and measures. Health risks associated with urban water systems and services include the microbiological and chemical contamination of urban waters and outbreak of water-borne diseases, mainly due to poor water and sanitation in urban areas, and the discharge as well as the disposal of inadequately treated, or untreated, industrial and domestic wastewater. Climate change only exacerbates these problems, as alternative scenarios need to be taken into consideration in urban water risk management. Urban Water Security: Managing Risks -- the result of a project by UNESCO's International Hydrological Programme on the topic -- addresses issues associated with urban water risks. The first section of the volume describes risks associated with urban water systems and services. The volume then discusses the concept of risk management for urban water systems and explores different approaches to managing and controlling urban water risks. A concluding section presents case studies on managing urban water risks.