O One form of water use is by utilizing water as a hydroelectric power plant. One of the hydropower plants that has been operating for a long time since 1923 is the Ubrug hydropower plant which operates with a run off river system and has a theoretical power potential of 18.36 MW. The purpose of this research is to identify the river discharge which is the water source for the Ubrug hydropower plant, to analyze the power potential of the Ubrug hydropower plant based on its discharge and water, and to evaluate the actual power of the Ubrug hydropower plant because the Ubrug hydropower plant has been in operation for a long time. It is necessary to carry out an evaluation to find out whether it is still operating optimally after operating for a long time and to find out what factors can hinder this performance.Based on the results of field data, analysis, and calculations. The actual power potential that can be generated by the Ubrug hydropower plant is smaller than the actual installed power. The reason for the decrease in the potential power that can be generated is due to the current water discharge from the Cicatih River which has decreased from the previous water discharge, due to changes in the function of the Watershed (DAS). into industrial development and forests upstream of the river which should be a source of infiltration has changed many functions to become residential areas so that there is less water catchment area around the power plant. Besides that, other factors are caused by the old hydropower machines and components and the large amount of garbage in the Cicatih river flow which is carried along with the water flow in the water channel