Verdict: It depends. Some dishwashers use a filter system that needs no regular cleaning, while many others have a removable filter that you're expected to rinse yourself; the design in your model decides it.
Where the idea comes from
A dishwasher spends its whole life spraying hot, soapy water, so it's natural to assume it keeps its own insides clean. Older dishwashers often had a built-in grinder that chopped food bits and sent them down the drain, and many people grew up never touching a filter. When newer, quieter dishwashers moved to removable filters, the habit didn't always follow.
What the evidence says
Whirlpool's page on cleaning the dishwasher filter describes two styles across its models:
- •A removable filter assembly at the bottom of the tub. You turn the upper filter a quarter turn counterclockwise, lift it out, pull it apart, and rinse it under running water, using a soft brush for stubborn soil or calcium deposits.
- •A system with a foreign object cup in front of the pump. Whirlpool says this design "does not require any regular cleaning or maintenance." You simply empty the cup when it fills with particles or objects.
The page says regular cleaning keeps water flowing strongly and helps stop food particles from recirculating through the cycle. On models with a Clean Filter indicator, you clean the filter, hold the Clean Filter button for 3 seconds, then open and close the door to reset it.
Even on models with a low-maintenance filter, the tub isn't left out. Whirlpool says dishwashers should be cleaned approximately every 30 days for best performance, and its interior cleaning page recommends a dishwasher cleaner monthly.
What to do instead
- Pull out the bottom rack and look at the floor of the tub. A round, twist-out cylinder means a manual filter; a small cup with a center tab in front of the pump points to the other style.
- Check the manual for your model's filter and its cleaning interval.
- For a manual filter, rinse it under running water and brush gently. Avoid wire brushes and scouring pads.
- Reinstall it fully, until it locks. A loose filter lets debris reach the pump.
- Clean the tub monthly with the product your manual names.
Exceptions worth knowing
- •Smells and gritty dishes are clues. A sour odor or sandy film on glasses often means a manual filter has been forgotten.
- •Hard water adds scale. Whirlpool mentions calcium deposits on the filter, which are common in LA County's harder water areas.
- •Standing water after a cycle can start at a clogged filter, but it can also be the drain hose, air gap, disposal connection or pump.
- •Tall items such as cutting boards or sheet pans can block the spray arms, which looks like a filter problem but isn't.
For a related question about load size, see whether running a half-empty dishwasher is wasteful.
Sources
- •Whirlpool: Cleaning the Filter, Dishwasher (two filter styles; rinse steps; Clean Filter reset; clean every 30 days)
- •Whirlpool: Cleaning the Interior, Dishwasher (monthly dishwasher cleaner)
The short version: Find out which filter you have; if it twists out, it's yours to rinse.
Clean filter, but still standing water or gritty glasses? TrueFix Los Angeles repairs Whirlpool dishwashers and the other major brands, and the number is (213) 787-3989.