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

The reuse of drinking water (direct and indirect; DPR/IPR) is increasingly being proposed as a strategy to strengthen urban water security in the face of climate variability and increasing demand. Although technological barriers have decreased considerably, many projects continue to face intense social and political conflicts. This article examines why technically viable reuse initiatives thrive in some contexts while failing in others, by developing a conceptual framework for analysing the conflicts associated with DPR/IPR. The study proposes three complementary typological matrices: Justification × Acceptance (J×A), Justification × Urgency (J×U) and Demands × Repertoires (D×R), which integrate the structural conditions of the projects with the strategic dynamics of the actors involved. The framework is illustrated by an empirical corpus of 25 global DPR/IPR cases, compiled through a realistic synthesis of academic literature, technical reports and contextual sources. The analysis shows that project trajectories do not depend solely on technological maturity or water scarcity, but on the interaction between technical justification, social acceptance, perceived urgency and, especially, the strategy and agency capacity of actors to mobilise 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.