摘要:The management of groundwater, a common-pool resource, is a fundamental collective action problem that can lead to over-exploitation. Our paper examines the management of two groundwater basins in California’s Central Coast region whose geographic proximity, land use patterns, socioeconomic characteristics, and timing of institutional formation provide an ideal basis for comparative study. However, each basin is governed by a distinctive institutional configuration. The Pajaro Valley Water Management Agency is a legislatively created Special Act District with a collective public management focus, while the Santa Paula Groundwater Basin is managed through a court adjudication with a rights-based focus. We compare the legal and administrative foundations of these institutional arrangements and examine their implications for the polycentric regulation of sustainable groundwater use. We find that while adjudication may specify groundwater rights, an approach that scholars argue can be critical for achieving sustainability, it also promotes insularity with a wider polycentric system and this ultimately limits its management strategies. The Special Act District, by contrast, does not encourage as clear an allocation of water rights, but does encourage a broad sustainability mission and wider polycentric engagement, though it still struggles with declining groundwater levels. Ultimately, neither institutional arrangement fully addresses the problem of groundwater sustainability. This suggests the need for further research on how institutional configurations and developmental pathways impact resource outcomes.