I had a home inspector write up a hydromassage tub saying it was not bonded. The tub was inside and the motor was outside. All the plumbing was plastic including the drain. The only two metal objects in the motor area were the motor/pump assembly and the junction box. So I bonded these two together. What else was there to do?
Now if the water supply pipes were metal, with the motor outside the building, would you have to bond the piping to the motor even though a person could never contact both at the same time??? These are the house plumbing pipes I am referring to, not the recirculation piping to the pump.
