I have water standing in the bottom of my dishwasher. This did not occurr until a new disposal was installed by yours truly. I found the plug I was to remove during installation an did so. Now the water drains. HOWEVER, now water stands in the bottom of the dishwasher after using the sink to rinse dishes. Is there some type of a check valve missing between the dishwasher and disposal??
Here is an install sheet for a dishwasher.
Note: the loop up in the drain hose.
http://products.geappliances.com/MarketingObjectRetrieval/Dispatcher?RequestType=PDF&Name=31-30515.pdf