This chapter explores how sustainable water governance may be fostered in a developing country by means of community based monitoring. A pioneering project in the coastal zone of Holbox Island in Mexico between 1999 and 2004 is analysed based on a framework to assess inputs and outcomes in initiatives for the public participation in research. The case study explores how actionable knowledge and evidence for learning was produced and discusses the merits and limitations of the project’s design and implementation. The case illustrates how citizens are empowered by being engaged in the production of scientific knowledge to solve environmental and development issues that affect their lives. For this, continuing efforts in capacity building and environmental education for the local community are important. It provides them with the knowledge and skills necessary to make appropriate choices for the preservation and development of their locality (Holbox) and the surrounding ecosystems. The two main lessons are that trust and openness between the researchers and the community are essential for the scientific success of the project and that in the absence of institutional supports, the continued survival of a project depends on personalities and goodwill.