I have a dishwasher with a drainline that runs into the bottom of the sink cabinet and into the garbage disposal.
When we don't use the dishwasher for a few days it starts to stink and we notice about an inch of dirty water in the bottom.
I recently installed a new garbage disposal and did the usual checks for leaks, which included running the dishwasher.
A minutes after the dishwasher had stopped I looked at the dishwasher drainline and I could see bubbles and water running backward from the bottom of the loop in the drainline, back toward the dishwasher.
The dishwasher drainline is looped about 4" higher than the disposal drain.
What am I doing wrong?