“Regional Infrastructure Foresight” enables municipalities, engineers and decision makers in regional sanitation systems to develop a middle- to long-term strategy for a sustainable sanitation infrastructure. Identification of uncertainties and future challenges of the regional infrastructure’s context is carried out in a participatory scenario process. A broad range of possible integrated solutions for the sanitation system is evaluated from different stakeholders’ views. This approach allows handling of uncertainties of frameworks and of complexity of the system to find more adaptive system configurations for a sustainable sanitation system.