Maytag quiet series 100 problem

Hello. I have a problem with our maytag quiet series 100. Everything seems to work fine and the dishes come out clean. The problem lies after the cleaning is done. In between uses, it seems that water starts to accumulate at the bottom of the dishwasher without it being on. We always empty the dishwasher after they are cleaned, so it could not be water from dishes or an overturned bowl. I was thinking it may have something to do with the connection to the garbage disposal and the water accumulated does appear to be dirty. What could be the problem? Thanks.

SLD