AbstractThis paper assesses the merits of polycentricity by looking at the water–energy nexus in the Spanish irrigation sector. In the last few decades, the Spanish electricity and water governance systems have transitioned from relatively monocentric, top‐down arrangements to arrangements that exhibit traits of polycentricity. This paper characterizes both governance systems against a series of polycentricity traits and provision and production activities. It then assesses the merits of the systems against the capacity of water user associations (WUAs) to adapt to water and electricity supply dynamics. The study relies on quantitative and archival data collected from a set of 38 irrigation systems located in north‐east Spain as well as secondary data from the broader water, energy and irrigation sectors. As illustrated in the analysis, WUAs can play a key role in integrating the management of water and electricity. They do so locally, via a diversity of institutional and operational adaptations. This role, however, requires sufficient levels of autonomy, clear rules that shape the interactions between WUAs and other water and electricity actors, and a relatively competitive environment.