Integrating Water Sustainability Strategies to Enhance User Comfort in High- Rise Residential Buildings in Lagos, Nigeria

Water supply reliability in high-rise residential buildings is shaped more by architectural design decisions than by the type of conservation technology installed. In Lagos, where municipal water supply is effectively absent, every high-rise building must function as a self-contained water supply system. This study investigates how water sustainability strategies including supply infrastructure, storage configuration, operational management, and conservation measures influence user comfort in four high-rise residential buildings in Victoria Island, Lagos. A post-occupancy evaluation (POE) framework was applied using methodological triangulation of resident questionnaires (n = 80), structured observational audits, and semi-structured facility manager interviews. Three composite performance indices were computed: the Composite Efficiency Index (CEI), Composite Satisfaction Index (CSI), and Operational Stability Index (OSI). Results show that the building with accessible pump rooms, layered storage provision, and a preventive maintenance regime recorded the highest scores on all three indices, with the difference statistically significant for efficiency and suggestive for operational stability, though not for satisfaction. Strikingly, the building with the most conservation infrastructure performed worse than the one with the simplest but best organised water system, showing that technology variety does not compensate for poor architectural integration. The study proposes a three-layer framework, covering hydraulic performance, redundancy and buffering, and operational integration, as a guide for embedding water sustainability strategies that genuinely improve user comfort. Diagnosing Environmental Drivers of Carbon Monoxide Concentration in