The theme of the recent Aqua Urbanica event, held on the Rigi by Eawag and the Swiss Water Association (VSA), was the importance of measurements. This year’s stormwater management conference focused on the value of sound data, the implications of gaps in knowledge for planning, and the process of digitalization in urban water management. The delegates agreed that the digital revolution is also transforming our sewer systems: following the impact on the sector made by microcomputers through physical modelling of water systems, the growing integration of real and virtual networks is offering new insights into wastewater management. Eawag’s Inkatypo3/ project (integrated regulation of sewer networks and treatment plants), for example, demonstrates how our sewer systems can be automated and more efficiently operated. Often, however, scientific foundations are still lacking: in the absence of a conclusive assessment of pollutants or mixture toxicities, for instance, it remains difficult to define ecotoxicological target values for discharges of storm and combined wastewater into surface waters.