Mdee, Ombeni J.Tembo, Malugu M.Mwegoha, William J. S.2023-05-252023-05-252022Mdee, O. J., Tembo, M. M., & Mwegoha, W. J. (2022). Estimation of storage tank capacities for different roof catchment areas for rainwater harvesting in Dodoma Urban, Tanzania. Tanzania Journal of Engineering and Technology, 41(2).DOI: https://doi.org/10.52339/tjet.v41i2.784http://hdl.handle.net/20.500.12661/4000Abstract. Full text article available at https://doi.org/10.52339/tjet.v41i2.784This study uses a mass balance model and economic analysis technique to present an estimation of roofing areas and storage tank capacity for Rainwater Harvesting (RWH) system. The water-saved benefits were estimated using the monthly rainfall of over 39 years from 1981 to 2020 and five roofing areas. The proposed roof-storage-ratio method presents the minimum requirement of roof area and storage tank size when the ratio value is closer to 1. The benefit-cost ratio and percentage of reliability indicated the optimal roofing areas ranging between 200 and 300 m2 for storage tank capacity between 20 and 25 m3, with a minimum discount rate of 5%. The increased capacity of storage tank and roofing area would also be a potential factor to increase the investment cost for installing the RWH system.enRainwater harvestingRoofing areaStorage tankRainwaterRainwater harvestDodomaTanzaniaArticle