As non-point source pollution has emerged as the leading cause of water quality impairment, governments have increasingly invested in community-based collaborative watershed initiatives to devise and implement strategies to address pollution problems. It is unclear however what social and environmental consequences exist for government involvement in such community-based collaborative efforts. The present study examines the Ohio Watershed Coordinator Grant Program, a six-year program in which state agencies offered funding, training and monitoring to community-based collaborative watershed organizations in Ohio. Through a comparative case analysis of 18 watershed organizations and in-depth longitudinal case studies of a sub-set of two organizations, we find that government involvement may yield a variety of impacts, some more positive than others, across the spectrum of organizational experience, from organization genesis to social and environmental outcomes. Such impacts vary by key organizational characteristics, such as type and age, and speak to emergent models in environmental management and governance literatures.