The main focus of this research line is the development of tools and methodologies to support the management of urban water systems (UWS). Line 12 seeks to integrate subsystems (such as sewer networks, wastewater treatment plants, water reuse facilities, and the receiving environment) and to support the planning of smart and sustainable cities. The main activities focus on three topics: digitalisation of the water sector; sustainable city planning, including Nature-Based Solutions; and integrated management of urban wastewater systems.