Recently bought a house on well water. A curious hum occurs in the wall behind the shower each time water is running. Ma0641 provided a prior solution saying it's caused by 'sympathetic resonance' which seems to be the case. Although the pump and tank are quite a distance from the house, I've discovered each time the pump cycles to fill the small tank is when the hum occurs in the house.
I can live with the noise but wondering if any damage could be occurring in the pump or tank when this happens?