This article examines the voluntary approach to environmental flow management in six western states of the United States. These states use the legal system for water allocation known as prior appropriation which allows market transfers of water rights or leases to beneficial uses, here for instream flows. Funding sources are required to provide for market transfers to e-flows (environmental flows), and the present study indicates the inadequacy of support. This article also explores management activities by states and non-governmental organizations as well as considers the meaning of governance for instream flows.