The efficiency of the solar PV array will decrease significantly as the temperature of the surface module exceeds a certain limit a nominal value. To handle the efficiency problem, it is important to control the surface temperature of solar PV. This study investigated the effect of the surface temperature of solar PV array modules due to automatic water spray cooling installed on the top roof of a residential structure in the Denpasar area. The performance indicator were then compared to that of the case without a water spraying cooling system. A thermostat is an automatic controlling system of cooling mechanism to keep the surface of solar PV temperature nearly to the ambient temperature. In this experiment, the surface temperature was kept at approximately around 330C with the active cooling system by the water spraying technique focus on the front surface of the PV module. The result presented an increase of PV voltage by 4.69% on average. Consequently, the output power produced by the cooled PV array module increase is 107.14 W against 94.01 W for the non-cooled PV array.