The purpose of this study is to investigate the pressure pulsation in piping systems with a discharge opening under water excited by a blower and its technological application. The effect of the cross-sectional area at the discharge opening was estimated experimentally. Both the pressure and the flow-rate in the piping systems were measured for various parameters such as the depth of the discharge opening, the number of revolution for the blower, and the cross-sectional area of the opening discharge. It was clarified that the amplitude of the pressure pulsation in the piping systems has the maximum value for the cross-sectional area at the discharge opening. The discharge pipe with the exhaust valve is effective against the rise of the instantaneous pressure in the piping systems.