Cluster I addresses a broad range of water-related research topics and establishes a scientific exchange between leading international scientists from a multitude of disciplinary backgrounds. Based on strong competence in water engineering, the safe water supply for various sectors and climate-resilient infrastructures are important concerns. To work towards these, experts on e.g. water treatment will cooperate with scientists in fields like building technology, economics, and geosciences. Beyond the focus on climate-resilient cities, other climate-adaptation-related problems such as sea-level rise, heat waves, droughts, storms, and their impact on rural agricultural systems are considered.