Abstract— Water is one of the renewable energy sources that can replace fossil energy sources for supplying electricity needs. Savonius water turbine is capable of operating at a low rotational speed and suitable for hydroelectric power plants using limited water head at wastewater pipe in the high rise building. However, this turbine has disadvantages at low power and torque coefficient. Research has been carried out to improve the performance of the turbine, such as varying the number of blades and angles of curvature in the prototype U-type turbine rotor. This study discusses the process of designing and testing a prototype of L type turbine rotor with three variations of blade arc angle; 120°, 135° dan 150°. The result shows that type L turbines with arc 135° blade angles have the highest power coefficient of 27% on a TSR of 1,32 compared to others..