Rainwater harvesting (RWH) technology are currently utilized in many locations in the world due to the sustainable benefits that it provides to the surrounding community. Their application in tropical countries is still minimal due to high rainfall variability and intensity, making tank design difficult to apply and optimize. This research aims to design and assess the efficiency of stormwater harvesting tanks in three tropical climate types for residential roof runoff management. Ten-year historical rainfall data was collected for assessment in the three study sites in the Philippines: a Type I, Type II/IV, and Type III representative site from different locations in the country, characterized by varying dry and wet seasons throughout the year. To accommodate the 90th and 95th percentiles of historical rainfall, a 0.7-1.1 m3 tank was recommended for construction in each residential site. A total of 59 events were then monitored on the selected sites to recalibrate the original design of the stormwater harvesting tanks. Compared with the initial size estimations, results indicate that nearly similar tank designs are recommended for the Type I and Type II/IV sites, attaining only a 7 % and 2 % decrease respectively, while a much smaller size would be deemed efficient for the Type III site, at least 59 % smaller than the original design.
