Reallocation is often promoted as a response to the U.S. West’s growing water insecurity. Water banking is a form of reallocation utilized in several western states to facilitate temporary water rights transfers. This article frames and examines water banking’s potential influences on water security from a hydro-social perspective through a case analysis of water banking policy in Utah. It analyzes challenges of integrating the market-based economic incentives of water banks with the legal precedents of the prior appropriation doctrine to reallocate water in over-appropriated basins with hydrologically interdependent uses. Key-informant interviews and focus groups were used to examine water security’s meaning to stakeholders and analyze how water banking could affect the water security of disparate users and uses at multiple scales. Stakeholders predominately saw water security as assurance in water quantity, but water security was further equated by participants with the legal protections afforded by water rights. Multiple complexities in water bank implementation are to be expected when multi-scalar contexts are considered, including societal and hydrologic tradeoffs in settings with diverse and interconnected interests. Our research shows that examining the potential ramifications of water banking policy through stakeholder perspectives can reveal nuanced insights on individual and collective water security issues not only within Utah, but other arid regions in general.