The aim of this study is to describe the development of an innovative planning tool to promote the knowledge and collaboration needed to overcome challenges in the sanitation sector. A serious game was designed to share knowledge about resource recovery and support attitude-change and collaboration between stakeholders. This study documents the co-design process of game development from conception based on a set of specifications the game should achieve, through iterative testing with relevant stakeholders as players. The resulting prototype of the game showed that it was not possible to include all the original desired specifications in the final game. Stakeholders found that the game was engaging, stimulated creativity and achieved its goal.