Planning and management of water resources are faced with increasingly high levels of complexity, uncertainty and conflict. Traditional technical and top-down management strategies have proved inadequate, forcing a move to more integrated forms of management, planning and decision making that can include stakeholders and communities, as well as technical experts and policy makers. These integrated forms of management require not only good technical or scientific ability, but a range of art-like skills including communication, creativity and the capacity to acknowledge and integrate diverse points of view. However, processes designed to aid such inter-organisational or multi-stakeholder decision-making are rare and in need of investigation. This paper proposes a process of participatory modelling using a series of semi-structured collective decision cycles which can aid decisions involving multiple stakeholders in water management and planning. The participatory modelling process outlined in this paper is designed to capture and integrate both tacit and explicit knowledge from stakeholders, right from the problem identification phase through to the final decision making, implementation and ongoing monitoring and evaluation. A brief idealised example of the participatory modelling process testing in Montpellier, France, is highlighted, as well as further questions and identified priority research areas.