Most all automatic dishwashers -- KitchenAid included -- come with a filter system inside the dishwasher to catch any food debris before it has a chance to clog your drains. The filter is in the bottom center of the dishwasher beneath the bottom rack and requires periodic cleaning to ensure free flow of the drain.
Newer KitchenAid dishwashers have a filtration system that consists of an upper filter cup and lower fine-mesh or coarse screen, both of which are removable. Older systems only allow you to remove the filter cup for cleaning, but leave the coarse filter screen in place. Besides filtering debris, the system enhances water and energy conservation while minimizing the noise of the dishwasher. Regular maintenance and cleaning ensures that your dishwasher continues to clean your dishes at its peak performance levels.
Remove the bottom tray to access the bottom filter assembly.
Grasp the circular filter inset in a screened filter in the center of the tub. Turn the upper filter assembly at least a quarter turn counterclockwise. Lift the upper filter assembly out of the lower filter assembly.
Grab the lower filter assembly by the edges of the hole for the upper filter assembly to lift it from the dishwasher.
Clean both filters by setting them under a running faucet. To remove stuck-on debris, use a bit of liquid dish-washing detergent and a soft toothbrush to remove it. Rinse clean and place both filters back in the dishwasher by following the installation steps in reverse.
Clean the coarse screen in place in older models with warm soapy water and a soft sponge. You can also pour a 1/2 quart of white distilled vinegar into the bottom of the machine and let it sit until overnight before running the dishwasher empty. Add detergent to the machine to help in cleaning its interior.
Homes with hard water -- noted by calcium and magnesium scaly buildup on sink and tub fixtures – require at least a monthly cleaning of the filtration system.
One to three washes per week: Clean your filter annually if you wash, scrape and rinse dishes before loading the dishwasher. If you only scrape the dishes without rinsing or washing, clean the filter twice a year. If you put the dishes in the dishwasher without rinsing or scraping, clean the filter the every two months.
Four to seven loads per week: For those who scrape the dishes before loading, clean the filter twice per year. If you do nothing to the dishes, clean the filter every month. Otherwise, if you rinse, scrape or wash, clean the filter annually.
Eight to 12 loads per week: Active households require cleaning the filter every two weeks if you do nothing to the dishes before loading the dishwasher. If you scrape only, clean the filter every three months. If you wash the dishes first, clean the filter once a year, but if you rinse and scrape, clean the filter biannually.
Two loads per day or 13 loads per week require a weekly cleaning of the filter if you don't scrape or rinse the dishes. If you scrape them first, clean the filter every three months. If you wash them first, clean the filter assemblies once a year or biannually if you scrape and rinse.