Common pool groundwater resources may be susceptible to overexploitation but can potentially be managed collectively. However, few studies explore the potential for successful collective action ex-ante. We conduct an ex-ante assessment of the potential for collective action by users of a groundwater body, to identify whether necessary conditions are in place, using a mixed methods approach based on literature, expert consultation, and Q methodology. While some aspects were conducive to collective action, under current conditions it appears unlikely that users will self-organize. Four user sub-groups were identified, differing in terms of resource perceptions and prosocial behavior, with potential for tapping into the skills of potential leaders and capitalizing on the prosocial intent of team players, while building bridges for cooperation with sceptics and non-users. Such ex-ante assessment can serve to identify which conditions need to be cultivated to foster cooperation and to identify strategies for engaging with different user sub-groups.