Watershed health and integrity are essential to human and ecosystem health and well-being. New River watershed communities in northern Belize, Central America are vulnerable to annual ‘cultural eutrophication’ - natural eutrophication exacerbated by human activity. Human-caused pollution from agriculture, septic effluent, and industrial drainage, in combination with extended drought and the slow flow of New River, has caused more frequent and prolonged periods of eutrophication. In this qualitative study, 42 New River residents were interviewed about river changes and impacts of eutrophication on their communities. Using the Community Capitals Framework to analyze resident perceptions, the study finds direct impacts from eutrophication on various sectors of society, namely environment, health, livelihoods, culture, and resource security. These impacts contribute to the vulnerability of New River watershed communities. The findings of this study can help policy makers and community leaders focus attention and resources to increase resilience of New River communities. Government policy and action recommendations are presented.