Design and Evaluation of a Rooftop Rainwater Harvesting System for Rural Household Use

Water scarcity in rural Philippine communities often undermines household and irrigation needs, yet empirical assessments of rooftop rainwater harvesting system (RWHS) performance under actual rural conditions remain scarce. This study aimed to design, construct, and evaluate a rooftop rainwater harvesting system (RWHS) for a rural household in Cabuluan, Villaverde, Nueva Vizcaya. It examined the volume of actual rainwater collected from January to May 2022 and evaluated the system’s cost-effectiveness in meeting domestic and irrigation demands. Results revealed that a total rainfall volume of 69.53 m³ could be harvested annually by the household, with a roof area of 36.25 m² and a roof slope of 12.33°, made of corrugated GI sheet roofing. Average rainfall amounts were based on 20-year rainfall data (1999–2018) obtained from the NVSU-PAGASA agrometeorological station 21.1 km from the study site. A storage requirement of 3 m³ was determined using the supply-side approach, which considers both rainfall patterns and household water demand. From January to May 2022, the system collected 0.81 m³, 2.19 m³, 0.66 m³, 0.69 m³, and 0.82 m³, respectively. These values excluded overflows from the storage system and rainwater during rainfall events. Variations in collected rainwater volumes and historical rainfall data were attributed to spatial differences in rainfall distribution. The findings indicated that the RWHS is a reliable water supply option for domestic and irrigation use at the household level. The total cost of constructing the rooftop rainwater harvesting system was approximately ₱60,000. The system offers convenient water access while contributing to environmental benefits, such as erosion control and stormwater management. By presenting actual collection data alongside long-term climatic records, this study fills a critical gap in RWHS performance evaluation under real-world rural household conditions, offering actionable insights supporting more sustainable and locally adapted water scarcity solutions.