Solar electric power generation utilizing photovoltaic (PV) modules is associated with low electrical efficiency that substantially decreases as its surface temperature exceeds an appropriate limit, particularly in hot climate regions. Consequently, it is required to keep PV modules relatively under a condition of low temperature using a cooling system as possible. The present experimental study evaluates the performance of the combined photovoltaic thermal (PV/T) module employing a water cooling system attached to the back surface during June for the city of Sohag in Egypt. The experimental results show that utilizing a water cooling system decreases the average surface temperature of the PV module from 44.8 °C to 30.3 °C on the back side and from 46.6 °C to 36.9 °C on the front side. The maximum value of the thermal heat gain of the PV/T module that is maintained at noon equals 230 W, and the corresponding value of the electrical power output is 34.4 W. Furthermore, the electrical efficiency of the PV/T module is 8% higher than that of the PV module without a water cooling system. Finally, the maximum and average values of the overall efficiency of PV/T module are 76.4% and 68.9%, respectively.