in an ideal world each appliance or sink would have its own outlet but when they share outlets they can affect one another ,resulting in extreme cases like trap seal loss where the smells created by one appliance can travel up another waste outlet.
would,nt the liqiud v powder affect the inside of the machine rather than what flows out of it
i have the same problem with a sink and dishwasher but when i alter the kitchen later this year i shall provide separate outlets