Globally, an estimated 748 million people remain without access to improved sources of drinking water and close to 1 billion people practice open defecation (WHO/UNICEF, 2014). The lack of access to safe water and adequate sanitation presents significant health and development challenges to individuals and communities, especially in low and middle income countries. Recent research indicates that aside from financial challenges, the lack of social capital is a barrier to collective action for community based water and sanitation initiatives (Levison et al., 2011; Bisung and Elliott, 2014). This paper reports results of a case study on the relationships between elements of social capital and participation in collective action in the context of addressing water and sanitation issues in the lakeshore village of Usoma, Western Kenya. The paper uses household data (N = 485, 91% response rate) collected using a modified version of the social capital assessment tool (Krishna and Shrader, 2000). Findings suggest that investment in building social capital may have some contextual benefits for collective action to address common environmental challenges. These findings can inform policy interventions and practice in water and sanitation delivery in low and middle income countries, environmental health promotion and community development.