This study aimed to define potential areas for forest conservation to improve water quality, using Multicriteria Evaluation (MCE); and to verify differences between results from a multidisciplinary group of experts. We worked with the Pirapora River Watershed, Piedade/SP. The participatory method was used to identify the criteria and their relative importance. Priority maps representing expert opinion were elaborated, as well as a map with average weight values. We compared the differences between the criteria weight values and the maps of priority areas. The maps proposed distinct spatialization of priority areas, supporting the understanding of criteria that influence the decision-making process. The highest priority level was associated with areas near to springs, forest patches, and with the highest slope values. We concluded that the MCE is an efficient method to identify priority areas; however, the selection of an expert group is an essential step to generate representative analyses.