This is driving my wife crazy! Our Bosch dishwasher (model SHU43C06UC / 14) leaves about 2" of standing water in the pump reservoir after each use. We have to squeegee out the dirty water before the next cycle. If we don't the dishware and utensils smell bad.
I've checked the evacuation hose all the way up to the air gap and through to the disposal. It's clear. Inside the unit, I've checked the impeller and rubber check valve for debris.. very clean.
Unit is about 13 years old. New pump maybe?