Diverse public policies encourage farmers to adopt eco-friendly practices to address the issue of diffuse pollution from agriculture, including measures based on the provision of information on the environment. Indeed, farmers’ perception of the state of the water body and their awareness of the causes and consequences of water pollution affect their willingness to adopt eco-friendly farming practices. Public policies therefore have a role to play in disseminating environmental information. In this article, we investigate how information measures may exert influence on changes in farming practices and thereby water pollution. We extend an existing agent-based model of a social-ecological system representing a drinking water catchment area. In the decision-making process based on the theory of planned behaviour we integrate a dynamical environmental component of farmers’ attitude towards eco-friendly practices, in order to take into account the effect of information on the ecological system. We explore the impact of information measures, heterogeneity in farmers’ environmental preferences and variations in the initial level of water pollution on farmers’ participation to a water catchment protection programme. Our results show that: (1) targeting farmers who have higher environmental preferences is more effective than no targeting; (2) the heterogeneity in farmers’ environmental preferences impacts their involvement in the programme depending on the average environmental preferences; (3) the higher the initial pollution, the higher the farmers are involved in the protection programme; (4) when two different measures are combined, once a certain threshold of public awareness is reached, there is a synergy between them.