Standing water in Maytag dishwasher

Dishwasher Repair
1

Maytag dishwasher model MDB5100AWW

After sitting empty for a day or 2 , the bottom fills with a half inch of dirty looking water. We had a repair man out and he replaced the water valve but it did not fix the problem. The dual kitchen sink does have a disposal on one side. Drain line issue ? Other possible causes ?

2

[COLOR=“Blue”]Drain line issue ? [/COLOR]
Since it is dirty water that would be my guess.

Although not for a Maytag here is a good install sheet.
http://products.geappliances.com/MarketingObjectRetrieval/Dispatcher?RequestType=PDF&Name=31-30515.pdf
Check that the drain is looped high enough.