This paper deals with the reflection produced when a waterhammer pressure wave encounters any device that produces a sudden energy loss such as an orifice, a valve, or an elbow. The classical wave theory is used to determine the magnitudes of the reflected and the transmitted waves. The waterhammer equations, with the friction term included, are solved by the method of characteristics. The conditions at a minor loss are studied as a boundary condition to these equations. Agreement between theoretical and experimental pressure-time diagrams is sufficient to validate the theory.