In many semi-arid, snow-fed river systems, climate change is shifting the timing and quantity of streamflow; at the same time, changing water use priorities are introducing additional demands on water supplies. These dynamics challenge water security across the globe. Water markets – economic instruments used to reallocate water via voluntary trade – may be used to adapt to these changes, though their implementation remains limited. To understand how water markets may enhance water security in the western United States, we assess diverse actors’ perceptions of water allocation institutions broadly, as well as their preferences for different water market designs, in the empirical context of the Walker River Basin. This 4,200-square mile watershed, located on the California-Nevada border, exemplifies many key regional water management challenges. Through an analysis of 30 in-depth interviews, we find that actors across sectors desire changes to traditional water allocation institutions, preferably at the local level, and view markets as an acceptable tool for reallocation. Despite identified legal and social challenges, markets that facilitate temporary water trading are generally preferred. While limited to the context of a single basin, these findings provide lessons for designing water markets to enhance water security in basins regionally and beyond.