The Pennsylvania State University Applied Research Laboratory has a 1.22 meter (48 inches) diameter closed loop water tunnel. The flow is driven by an axial pump with three blade rows and powered by a 1.5 MW motor. The four blades of the impeller have the highest relative velocities of any lifting surface in the facility, and generate input acoustic power which acts as a background noise floor in tunnel measurements of turbomachinery and vehicle body performance. In this paper, we investigate the sound power radiated by the impeller and its propagation through the water tunnel. Trailing edge hydrodynamic forcing functions are computed for the impeller based on local relative velocities and turbulence properties. For lower frequencies, these forces are then applied to an experimentally validated structural finite element model (FEM) of the impeller. The input power to the water tunnel is determined using an acoustic boundary element model (BEM) of the impeller. A statistical energy (SEA) model of the water tunnel allows for an estimate of the rms pressure within the water tunnel test section to provide guidance on lowering background noise.