Water flow through valves and orifice plates in a piping system is a source of high noise levels when cavitation occurs and, since the noise is propagated easily by the structure and fluid of the system, severe acoustic problems can arise. Laboratory measurements have been made to determine the fluid-borne and structure-borne noise characteristics of a series of valves and orifices in the pipe size range of 1 to 4 in., for flow speeds up to 16 ft/sec and pressures to 130 psig. The influence of parameters such as flow speed, pressure, orifice diameter, and valve size are considered with respect to level and frequency content of the noise propagating in upstream and downstream directions. The results show that, for example, orifice diameter and flow velocity have negligible effects on the dominant frequencies in the noise spectra. The use of flexible hoses to reduce noise propagation is discussed.