Predicted climate change may significantly affect drinking water supply in urban areas. Local water stakeholders facing climate change will have to deal with uncertain information and unexpected events. To address this lack of data, the knowledge and experience of practitioners might be used to assess the potential impacts of climate change on different issues, including drinking water supply. This paper proposes a participatory approach to identify local issues associated with drinking water supply (from source to tap) in a climate change context. This approach relies on the experience and knowledge of local practitioners. The proposed approach was applied to the Québec City metropolitan area (Province of Quebec, Canada). It is based on assignment examples (in this case, a selected set of districts from the study territory) in order to generalize application to the entire territory. This approach helps stakeholders to rationally consider different dimensions and the complexity of drinking water supply.