I've always been annoyed by the whining noise made by the sink water pump
whenever it is turned on so I seized the opportunity to do something about it
when the pump finally died recently. This morning I replaced the pump with a
similar one purchased at a local RV dealer. Before securing the pump to the
cabinet floor, I placed a 1/4 inch thick rubber pad between the floor and the
pump to absorb any vibrations and noise. I mounted the pump to the floor by
screwing the mounting brackets through the rubber pad and into the cabinet
floor. Next, I cut a small cardboard box (approximately 4" X 2" X 3") so it
would enclose the pump when placed upside down over it. I cut a few pieces of
dense foam to line the inside of the box to further absorb sound and vibrations.
This sound absorbing box is placed over the pump before replacing the cabinet
cover which hides the pump. It took about thirty minutes to make and does a
reasonably good job of muffling the noise created by the pump.

Roy O.
'87 Westfalia
('till death us do part)