An evidence-based assessment of decentralized and local water management concepts and how they relate to smart city concepts is presented. Decentralized water management is based on the principle of integrated water cycle management and water-sensitive urban design. A “smart city” is generally defined as a city seeking to address public issues via information and communication technology (ICT)-based solutions on the basis of a multi-stakeholder, municipally based partnership. Using evidence-based review principles it is shown that when ICT is applied to water management in cities, it enables the collection of data for better understanding of how a city functions and to improve it to the benefits of its inhabitants and the environment.