In Canada, the multi-barrier approach allows for a multi-dimensional water management, using tools and practices to ensure safe water, from source (lake, river, etc.) to citizens' taps. As one of these barriers, source water protection (SWP) seeks to anticipate or reduce natural and anthropogenic risks that could alter the sources. In this context, the Government of Quebec has adopted the Water Withdrawal and Protection Regulation (WWPR), which reinforces SWP in Quebec. However, the implementation of the WWPR implies the development of action plans that require the acquisition of a multidisciplinary knowledge on water quality, quantity and on the natural and socio-economic components of the territory. This paper aims at providing a diagnostic portrait of the implementation of SWP in Quebec, in order to identify the decision-making process, its stakeholders, and the knowledge generated and mobilized for decision-making. This portrait is based on an online survey conducted between November 2018 and March 2019. The qualitative and quantitative analyses of 208 responses revealed that SWP implementation is currently characterized by a great diversity of the stakeholders involved, tasks and knowledge created, and a strong inter-organizational dynamism. However, it is noted its decision-making process becomes less inclusive as it moves through the implementation stages, that knowledge is sometimes redundant and that there are many knowledge transfer issues (access, quantity or quality of knowledge) between stakeholders.