The increasing operating temperature of the PV panel decreases the efficiency and the life time of the solar panel. This numerical study aims to investigate a design of water-cooling system for PV module using computational fluid dynamics (CFD). The design of a water-cooling system for a domestic PV panel in Singapore was proposed in this paper. The proposed design was applied at the bottom surface of the PV panel to decrease the temperature of the system. The results showed that the circulated water through the heat exchanger dissipated heat from PV module. After conducting a computation fluid dynamics simulation in ANSYS with two different materials (Steel and copper), it was observed that the model was able to reduce 6°C of overall PV module temperature and performed best at a flow rate of 40 kg/min (0.667 kg/s) with low conductivity materials.