This paper aims to identify drivers and barriers to the achievement of EU water policy objectives in the agricultural sector by adopting an institutional perspective on water quality management at the landscape level. We apply a conceptual framework combining Integrated Landscape Management (ILM) and Institutional Design Principles (IDP) perspectives to analyze cooperation initiatives involving water suppliers and agricultural stakeholders to protect drinking water catchments from agricultural diffuse pollution. Three cases representing different forms of cooperation in rural landscapes in France were investigated on the basis of primary data collected at the local, water-basin and national levels. The results show that the success of multi-stakeholder collective action depends on both local factors such as characteristics of the water resource and stakeholders (knowledge, resources, trust and social capital) and on factors linked to the EU and national water and agricultural policy frameworks. In addition to the identification of drivers of and constraints on the implementation of EU water policy in agricultural landscapes, the analysis highlights the conceptual added value in combining the IDP and ILM approaches to understand policy implementation processes at the landscape level.