This is a case history in which the sound power level was determined for an abrasive water jet cutting system in a semi-reverberant test environment. The water jet was tested with a conventional water tank catcher and a small ball matrix developmental catcher. The sound power of the associated pump and high pressure lines under a no-flow condition at operating pressure was also determined. The study used the one-third octave bands from 100 Hz to 20 kHz.