Answer Tom, Here's some information that should help you out " A common problem with these units is the piston and nut (Item 564 in Section 2). It is behind the rear filter assembly in the tub. It unscrews. Remove it and check that it is sealing. What happens if it does not seal correctly is that during drain some of the water goes back into the tub instead of out the drain. Read more: http://forum.appliancepartspros.com/dishwasher-repair/234514-dishwasher-standing-water.html#ixzz1SeqXcJXW'>http://forum.appliancepartspros.com/dishwasher-repair/234514-dishwasher-standing-water.html#ixzz1SeqXcJXW http://forum.appliancepartspros.com Thanks and Good Luck Read More... Answered by AppliancePartsPros.com | Wednesday, July 20, 2011