Sustainable Water Management and University Operations: A Systematic Review of Rainwater Harvesting, Water-Saving Technologies, Greywater Recycling, and Demand Management Strategies and Their Effects on Water Conservation Outcomes at the University of Ibadan, Nigeria

Water conservation constitutes an urgent sustainability challenge for Nigerian federal universities amid increasing water scarcity. The University of Ibadan (UI), Nigeria’s oldest university, reflects the cumulative effects of deferred infrastructure maintenance, expanding student population, and the absence of systematic water demand management. This review examines the potential of sustainable water management strategies to produce measurable conservation outcomes at UI. A systematic review was conducted following a protocol-first approach with a predefined PICO-structured research question, comprehensive multi-database search, explicit inclusion and exclusion criteria, two-stage independent screening, standardised data extraction, critical appraisal using the Mixed Methods Appraisal Tool, and thematic synthesis. The theoretical framework integrates political economy of water governance, social-ecological systems resilience, behavioural psychology of conservation, and institutional design for com- mon-pool resource management. The review identifies five key intervention categories: rainwater harvesting systems leveraging Ibadan’s ~1,200mm annual rainfall for non-potable use; water-saving technologies such as low-flow fixtures and sensor taps; greywater recycling systems for irrigation and toilet flushing; smart metering for leak detection and consumption monitoring; and demand management strategies combining education, behavioural nudges, usage targets, and conservation pricing. Evidence from international and African contexts suggests these interven- tions can reduce per capita water consumption by 30–50% within five years when properly implemented and institutionally supported. However, UI currently exhibits unmetered supply systems, deferred maintenance, and no structured conservation programme. Outcomes are therefore highly dependent on infrastructure reliability, governance strength, and institutional commitment. Sustainable water management at UI is technically feasible and empirically supported but requires a shift from isolated infrastructure provision to embedded institutional practice. Effective outcomes depend on coordinated technical, behavioural, and governance interventions supported by sustained institutional investment and accountability structures.