Urban pluvial floods (UPFs) are a threat that is expected to increase with economic development, climate change, and the proliferation of urban cover worldwide. Methods to assess the spatiotemporal magnitude of UPFS and their impacts are needed to research and explore mitigation measures. This study presents a method for the assessment of UPFs and their impacts by combining a hydrodynamic sewer system model with a GIS-based overland diffusive flow algorithm. The algorithm is implemented in the software GIS-based Agent-based Modeling Architecture (GAMA) along with the depth-damage functions and land use data to estimate financial impacts. The result is a dynamic and interactive model that allows the user to monitor the events in real-time. Functionality is demonstrated in a case study in Dresden, Germany and with ten to 100-year design storms. The majority of flood extents and damages occur in the early stages of the event. Sewer surcharge emerges from few of the manholes, suggesting early action vitally reduces flood risks and interventions at a few hot spots, largely reducing impacts. Flood protection barriers were interactively implemented as a potential response measure in the hot spot areas reducing the damage by up to 90%. The user can compare different parameters in a visually compelling way that can lead to a better understanding of the system and more efficient knowledge transfer.