Despite considerable investment, sustainability of rural water resources remains a critical challenge in Ethiopia. Evidence suggests social capital – the networks, norms, and trust that facilitate cooperative behaviors – influences a community's ability to manage communal water resources. In turn, strong community governance of water resources may lead to sustainable resource management. Existing evidence provides a framework for exploring the relationship between social capital and governance of common-pool resources. However, there is a dearth of quantifiable evidence demonstrating the relationship between social capital, collaborative governance, and, in turn, sustainability of communal water resources. In 32 communities in rural Ethiopia, we employed a validated survey tool, developed by the World Bank, to quantify social capital and explore these relationships. We found associations between governance and several social capital domains: groups and networks, trust and solidarity, and information and communication. All governance indicators were associated with functionality. Identifying domains of social capital that influence governance can inform institutional efforts to target community-based water resource programming, foster social capital to improve water point sustainability, and diagnose issues related to resource management. Additional research examining the influence and directionality of social capital and other social constructs on water resource governance and functionality is warranted.