Yes, oftentimes the pumps can be noisy. If you do some poking around on the internet, you will see some kits to make pumps quieter as well as suggestions. Many claim that it's the hoses connected to the pump (which are stiff) vibrating; others feel it's the vibrations from the pump where it is connected to the RV. As a result - some of the kits or suggestions add loops of more flexible hose where they connect to the pump, and some cushion the mounts. Personally, I've cut up an old rubber mouse pad in the past and re-mounted the pump with the cushion in place.
Not sure if this helps, but your observation is a common one.
2008 Journey 39Z Cummins 350 ISB 6.7L
2006 Honda CR-V LX Tow