The declining North Sumatra’s Lake Toba water level caused PT Inalum to request BRIN to replenish the lake through cloud seeding to meet the electrical power production. Cloud seeding was conducted from April 1 to 29, 2021, during the transition of rainy and dry seasons. The Piper-Cheyenne aircraft equipped with CoSAT-1000 hygroscopic flares departed Silangit Airport for the daily seeding missions. The seed clouds are selected carefully to meet seeding criteria using radar monitoring. Evaluation of activity results using rainfall data taken from GSMaP data using the Target Only Statistical Method. Actual and historical rainfall data (2001–2020) are taken from GSMaP data. According to this study, precipitation has increased by 36.3%. The spatial distribution of rainfall demonstrates an upward trend, with greater values observed in the eastern region of Lake Toba. Cloud seeding has also increased Lake Toba’s level by 8.5 cm. In addition, it has also produced an additional inflow of 5.29 m3/second, equivalent to a water volume of 13,254,624 m3, comparable to 15,905,548.80 kWh. It is hoped that the outcomes of this work will help provide food and energy security by supplying water to dams in Indonesia.