Water motor gong, also known as sprinkler alarm or water motor alarm, is a hydromechanical automatic sound warning device actuated by water flow. It is usually conjunct with alarm check valve, dry pipe valve, or deluge valve to sound a local alarm.

While sprinkler system operates, water passes through the water motor gong, the impeller turns and the shaft rotates by high velocity water jet, and the rotating shaft drives a striker assembly which rings the gong, sounding a continuous alarm.

Main parts and feature