Product review (1 stars): After spending over an hour on the phone with whirlpool ...
After spending over an hour on the phone with whirlpool, we discovered what we feel is an international design flaw so that they can sell additional products (afresh) or save money by eliminating a check valve from the drain line.  Without a check valve the residual water in the line llcan flow back into the filter area when the washer has finished its cycle.  Yes, it is only about 6 ounces that remains in the bottom of the dishwasher in the filter area, but this stagnant water will develop an odor and become slimy (water mold?) over time.  All dishwashers made by the same manufacturer as whirlpool (jenn aire, Maytag, admiral, Amana etc) have eliminated this check valve from their dishwashers.  We have 5 rentals and have they all have fridgidare dishwasher with check valves and they have absolutely no problems.  This is our second whirlpool over the years.  We did not have this problem with the prior model as it had a check valve. BUYER BEWARE there is no fix for this.