Dear Karen,
This has more to with commonsense than feng shui. For example, here one would certainly wish that they stay in a concrete reinforce-cement home. This is because when the washing machine spins it does shake.
If one house is made of wooden planks or thin gypsum wooden walls, then sometimes the washing machine may vibrate and this vibration can be felt at the opposite wall plus the noise can be heard.
So the only solution is try to place the washing machine too close to the wall. Not much else you can do unless there is space elsewhere that you can relocate your washing machine.
Hope that helps.
Warmest Regards
Robert Lee