Your glasses come out with a gritty film. Your plates have little bits of food stuck on them. There’s a sour smell when you crack open the door in the morning. So you switch detergents, run a hotter cycle, start rinsing everything by hand. Nothing really fixes it.
Here’s what’s going on: your dishwasher isn’t broken, and your detergent isn’t the problem. There’s one small part inside your machine that almost nobody knows they’re supposed to clean. And every month it goes untouched, your dishwasher gets a little worse at its one job.
The fix takes about three minutes, costs you nothing, and you don’t need to call anyone.
Why your dishwasher slowly stops working
Modern dishwashers don’t fill up with clean water and drain it after every rinse. They fill up once with a small amount of water and then spray that same water on your dishes over and over for the whole cycle. That’s how a new Energy Star dishwasher can get by on as little as 3.5 gallons (13 liters) per load, according to the U.S. Environmental Protection Agency.
But this only works if the food coming off your dishes gets caught somewhere and stays there. If it doesn’t, the machine is basically spraying your plates with dirty water.
Larry Ciufo, a mechanical engineer at Consumer Reports who’s tested more than 500 dishwashers over 15 years, put it simply: something inside the machine is supposed to stop food from ending up back on your clean dishes. When that part stops doing its job, your dishes get dirtier and dirtier, but so slowly you don’t notice from one load to the next.
The thing almost nobody knows changed
Here’s the piece most people have no idea about. Up until around 2010, most American dishwashers had a self-cleaning system built in. Basically, a little grinder chopped up any food and flushed it out with the drain water. You didn’t have to think about it. Then the industry changed.
According to Consumer Reports, the big brands moved away from those self-cleaning systems because the grinders were noisy and used more power. The quieter, more energy-friendly dishwashers everybody loves now came with a small catch nobody really told you about: the cleaning job is now on you.
If your dishwasher was made in the last 10 to 15 years, there’s a good chance it has the newer style. And there’s an even better chance that in all the years you’ve had it, nobody has ever touched this part.
What actually happens when you skip it
The problem builds up so slowly that almost everyone misses it.
- Month one: Bits of food start collecting in a small mesh piece at the bottom of the tub. You don’t notice a thing.
- Month three: The mesh gets clogged. Water passes through it, picks up old food and grease, and sprays it right back onto your dishes. Everything looks “clean enough,” but glasses feel a little rough.
- Month six: That sour smell shows up. A 2018 study by scientists at the University of Copenhagen and the University of Ljubljana, published by the American Society for Microbiology, looked inside real home dishwashers and found germs growing in there, including E. coli and yeast. The key finding for you: the more you use your dishwasher, and the harder your tap water is, the more of this gunk builds up.
- Month twelve: Now the gunk that used to get caught is getting past the mesh and clogging up the water pump inside the machine. This is where a $0 chore turns into a repair bill. Bosch says on its own support page that this kind of buildup, left long enough, can “seriously damage” the dishwasher.
By this point, you’re pretty sure your dishwasher is dying. It isn’t. It’s just choked up with a year’s worth of dinners.
The part you’re looking for
Ready? The part is called the filter. On almost every dishwasher built since about 2010, it sits in plain sight on the floor of the tub, in the middle or slightly toward the back, under the bottom spray arm.
Pull out the bottom rack and look. If you see a small round piece sticking up (usually plastic, sometimes with a flat mesh screen next to it or under it), that’s the one. Whirlpool, KitchenAid, GE Appliances, Bosch, and Samsung all put it in about the same spot, and all five say on their support pages it’s meant to be pulled out and rinsed off.
If instead you see a flat plastic grid over the drain with nothing to twist, you probably have the older self-cleaning kind, and you’re off the hook. GE Appliances says a lot of its older models, and even some current ones, still work this way with nothing you need to clean.
The 3-minute fix
Every step below matches the official instructions from Whirlpool, KitchenAid, and Bosch.
Do this:
- Pull the bottom rack all the way out so you can see clearly.
- Grab the round piece in the middle and turn it to the left about a quarter turn. It should unlock and lift straight up. If there’s a flat mesh screen underneath, take that out too.
- Rinse both pieces under warm water at the kitchen sink until the water runs clear. You’ll probably be grossed out by what comes out.
- For stuck-on grease, use a soft brush or an old toothbrush. Whirlpool says this straight out: don’t use a wire brush or a rough scrubbing pad because they’ll damage the mesh.
- Wipe out the empty spot in the tub with a damp cloth while you’re in there.
- Put the flat mesh back in first, then set the round piece on top and turn it to the right until it clicks and locks in place. If it spins freely, it’s not locked. Try again. Whirlpool warns that running the dishwasher without this part locked in can hurt the machine.
That’s the whole thing. Three to five minutes, no tools, zero dollars.
How often to actually do it
The manufacturers pretty much agree when you check their own official pages.
- Whirlpool and KitchenAid: once a month for normal use, every 2 weeks if you run it every day or you have a big family.
- Samsung: at least once a month, even if the inside looks clean.
- Bosch: every few months for light use, more often if you use it a lot.
- Consumer Reports: every couple of months as a basic rule.
A safe rule for most homes: once a month. Bump it to every 2 weeks if you run it daily, have hard water, or don’t scrape plates before loading.
One habit that makes this way easier
Scrape your plates. Don’t rinse them. The EPA’s Energy Star program says today’s dishwashers are built to handle dirty dishes just fine, and rinsing everything first can waste up to 20 gallons (76 liters) of water per load. Today’s detergents actually need a little food to grab onto to work right.
Big chunks in the trash, the rest for the machine to catch.
What changes on the very next load
You’ll see a difference the first time you run it. Glasses come out clear. The gritty feeling goes away. The sour smell in the morning is gone. You’ll also get more years out of the machine, because the pump can breathe again and the spray arms spray at full power.
Your dishwasher isn’t old. Your detergent isn’t wrong. There’s just one small part on the floor of the tub that almost nobody knows to touch, and now you do.
Sources: (1) Bosch Home US, “Dishwasher Cleaning & Maintenance”; (2) Whirlpool Product Help, “How to Clean the Dishwasher Filters”; (3) KitchenAid Product Help, “Filter is Dirty – Dishwasher”; (4) GE Appliances Support, “Dishwasher – How to Clean Fine and Ultra Fine Filters”; (5) Samsung Support, “How to clean a dishwasher filter”; (6) Consumer Reports, “How to Clean Your Dishwasher Filter”; (7) Consumer Reports, “How Often Should You Change the Filters in Your House?”; (8) U.S. EPA Energy Star, “Dishwashers”; (9) Raghupathi et al., “Microbial Diversity and Putative Opportunistic Pathogens in Dishwasher Biofilm Communities,” Applied and Environmental Microbiology, 2018
