Product review (5 stars): Easy fix!
I started experiencing problems with my KitchenAid dishwasher... when not in use, the tub would fill with water when the unit was not in use.  Logic told me it had to be an issue with the water valve, so I did some research and found this inexpensive part available on Amazon.  It took me about 30 minutes to install the part, and my problem was resolved.

On my model, the water valve is located on the bottom of the dishwasher near the front, but in order to easily access the area I uninstalled the dishwasher and flipped it on it's side.  Once I did that, it was very easy to swap the part.