Renewable energy systems are increasingly being developed to meet the demand for electrical energy while minimizing their environmental impact. Daily domestic water supply is stored on the top floors of buildings. This water generates pressure that can be harnessed to produce small-scale electricity. Using small-scale water turbines with low power output, minimal environmental impact, and low infrastructure costs, connect to a voltage converter to generate useful electricity for small device applications. This paper introduces the proposed multi-input DC-DC converter with different voltage levels controlled by MPPT, and PI algorithms to optimize the power output from the water turbines, achieving high efficiency with a wide input range and stable output voltage. The system includes a boost converter at the input stage and a buck converter at the output stage. The boost converter generates a stable output voltage of 35 V, while the buck converter produces an output voltage of 12 V with a high current. At a load current of 1 A, it achieves an efficiency exceeding 90%, significantly outperforming traditional designs.