the most common forms of damage mechanisms in water transportation pumps are cavitaion, erosion and corrosion. Type and intensity of failure mechanisms are affected by type of fluent, operation condition, and materials which are used in pump fabrication. Realizing the active mechanisms on failure of booster pump's inner surface was the aim of this investigation. In this study, scanning electron and optical microscopy and image analyses software were used to investigate morphology. Corrosion rate was measured by electrochemical test and water analyses. The results showed that cavitaion was the main mechanism of failure. In addition, scanning electron microscopy images and total hardness of feed water prove the erosion mechanism.