All the pumps will hum--isolating them from the mounting board is the first solution. Rubber feet/grommets/any type of soft padding. Are you sure it is the pump itself, or a water line touching a wall? Normally, we barely hear ours, but every now and then, it rattles some, then stops.
2016 Tiffin 40 QBH
2015 38RSSA, traded
2005 TK3 #1869, 10 yrs of memories,
2017 F450 KR--one more Ford is it
2009 F450 4x4-died; 2010 F450-retired