If you have water remaining in the bottom of your dishwasher then I would check the following:
- The drain filter screen is free from food byproducts that might limit drainage.
- The drain line exiting the dishwasher itself.. is it kinked or clogged?
- If your drain line is plumbed into a garbage disposal side entry, is that clogged or your house drain clogged?
- Is your dishwasher pump contaminated with sediment or anything that would limit its ability to pump?
- Are the water lines that come into or out of the pump blocked, damaged or restricting water flow?
Those are the main reasons areas of concern to investigate.. BTW, your drain line exitting the dishwasher should be routed up high and down into your sink drain system or thru the garbage disposal tap so that you have an air gap as 20YRSEXP was inquiring about..
You can run a simple test to verify all this..
Detach your drain hose from the house drain system ( from the garbage disposer or sink drain.. then route that into a rubber barrel ( be sure to keep part of the house up around the height of the countertop when you do this.. )... You should see a fairly robust flow of drain water into it when the system functions properly.. I would encourage you to run this test with no dishes inside it,.. This test will tell you if the restriction is in the dishwasher or house drain side..
Hope this helps you..