Reuse of Drinking Water in the Cities: Types of Conflict, Legitimacy and Governance

Potable water reuse (direct and indirect; DPR/IPR) is increasingly proposed to strengthen urban water security under climate variability, water scarcity, and rising demand. Although technological barriers have decreased considerably, many projects continue to face intense social and political conflicts. By developing a conceptual framework to analyze the conflicts associated with DPR/IPR, this article examines how justification, acceptance, urgency, and actor agency interact to shape why some technically viable reuse initiatives are consolidated, transformed, or blocked. The study proposes three complementary typological matrices: Justification × Acceptance (J × A), Justification × Urgency (J × U), and Demands × Repertoires (D × R). These matrices integrate the structural conditions of the projects with the strategic dynamics of the actors involved. The framework is illustrated by a comparative international corpus of 25 DPR/IPR cases, compiled through a realist synthesis of academic literature, technical reports, institutional documents, and media evidence. The comparative case synthesis suggests that project trajectories do not depend solely on technological maturity or water scarcity. Instead, they are driven by how configuration changes and the strategic capacity of actors shape collective demands, narratives, and repertoires of action. Consequently, the advancement, transformation, or blocking of potable reuse projects is mainly explained by how these strategies shape the legitimacy of water risk governance.