Innovative decision making for sustainable management of water aims at providing tools needed if any integratedand participatory management of water should be carried out. Management refers in this context to its core element,the decision making process (DMP).Focusing on water supply and sanitation (as there the need is paramount), DIM-SUM will carry out one case studyin one river basin in each participating partner country, Indonesia, Maharashtra-India, Malaysia and Nepal, in orderto evaluate and develop these tools. They will on the one hand encompass tools to generate, assess and comparetechnical scenarios, ranging from argumentative to computational, and fragmented to integrated methods, and onthe other, tools to enhance a participatory decision making, including information & communication technologiesand hybrid methods. The most innovative deliverable of DIM-SUM will be recommendations for a sustainable DMP encompassing anadaptive tool box (comprised of several tools, where the user can select those fitting to her/his needs), guidelinesand policy recommendations, which will enable local decision makers to carry out an assessment of technicalscenarios at an appropriate level of integration and participation. In particular, facing impairing quality and quantity of natural resources, an integrated and participatory DMP becomesvital. Environmental resource efficiency has to be balanced with the risks of technical systems (technical, economic, social, environmental risks), and many other aspects. DIM-SUM is motivated by the fact that such exercises are usually carried out in a superficial way only, despitethe international call for an integrated water management. Therefore, DIM-SUM will involve a wide range ofstakeholders in the project, ranging from NGOs to governmental and international organizations.