This article demonstrates the links between two approaches: one based on integrated water resources management and the other on social economy principles. It does so using an analysis of environmental, social, and economical impacts resulting from a provincial program for the improvement of septic systems in New Brunswick managed by watershed associations of the Acadian coast between 2003 and 2007 (southern Gulf of St. Lawrence). The first part of the article presents the importance of watershed management and the concepts of integrated water resources management, and of social economy. Then, the results of the analysis done are presented using a participative partnership research, and interviews, and focus groups. The results of this study show the social contributions of the various watershed groups to the social economy, sustainable development and integrated management of New Brunswick.