How to unclog a dishwasher

woman unclogging a dishwasher

Danny Baggs

Posted August 02, 2022

Is your dishwasher failing to drain correctly? Here are simple instructions on how to unclog your dishwasher.

If your dishes are still dirty after a cycle in the dishwasher or water keeps mysteriously appearing on your kitchen floor, you might have a clogged dishwasher on your hands.

Blocked drains can happen more frequently than you might think: RACV Trades plumbers were called out 8,742 times in 2021 due to blocked drains and pipes from sinks, toilets, dishwashers and other household drains, according to RACV Homes Trades & Services Senior Product Manager Nathan Tayeh.

Unclogging your dishwasher: everything you need to know

Is my dishwasher clogged?

“Sometimes it can be fairly obvious when your dishwasher is clogged,” Tayeh says. “You could see an error message on its display or spot water all over your kitchen floor. You could also notice grimy water sitting in the bottom of your dishwasher or discover that your dishes are still dirty after a cycle.”

Other dishwasher owners might hear unusual sounds like gurgling, shaking or thumping during a dishwashing cycle, which could indicate that water is struggling to drain through a clog. Unusual humming or clicking may mean that the pump and motor need replacing by a professional.

Why is my dishwasher clogged?

Food scraps are the number one cause of dishwasher clogs. “Large bits of food that haven’t been properly scraped off your plate can block both the filter and the drain hose,” Tayeh explains. Other clogs can be caused by children’s toys and dislodged dishwasher machine parts.

food scraps caught in dishwasher filter

Large food scraps are often the culprit of dishwasher clogs. Image: Getty

How do I unclog my dishwasher?

Before calling a plumber, there are several simple things you can do to try and fix a minor dishwasher clog yourself.

  1. Remove your dishes and racks – safely set aside any dishes and racks that were inside the dishwasher. 

  2. Try re-running the cycle – if someone accidentally opened the dishwasher before its cycle finished, it might not have had time to drain. Rerun the cycle to make sure your dishwasher is clogged.

  3. Attempt a quick fix – you could pour a cup of baking soda followed by a cup of vinegar into the standing water at the bottom of your dishwasher, then leave it for about 20 minutes. If the mixture has started draining, rinse it with some hot water and run the dishwasher’s rinse cycle.

  4. Disconnect your dishwasher – if that doesn’t work, it’s time to investigate. Turn off the electricity running to your dishwasher to keep yourself safe from electrical shocks. Make sure to entirely unplug the dishwasher.

  5. Remove any standing water – scoop out any water pooled at the bottom of your dishwasher with a cup or bowl, then dry the remaining dampness with an old towel.

  6. Clean the dishwasher filter – remove the dishwasher’s filter/s: usually a twist-off cylindrical filter plus a flat, grate-like filter at the bottom. Give the filters a thorough clean with warm, soapy water to remove any debris. Make sure to wipe out any debris in the area before replacing the filters.

  7. Reconnect your dishwasher – re-insert your dish racks and switch the power back on before running a cycle to see if your efforts have been rewarded.

  8. Call a professional – if you haven’t been able to locate the problem or your dishwasher is still not working properly, it’s time to call a a qualified plumber.

man's hand removing the filter from a dishwasher

You should check your dishwasher's filters for clogs. Image: Getty

How do I prevent dishwasher clogs?

To help prevent future dishwasher clogs, make sure to scrape large food particles off your dishes before loading them in. That said, you should refrain from thoroughly rinsing your dishes before loading them into your dishwasher. This can fool the dishwasher’s internal sensors into thinking that your dishes are cleaner than they are.

Regularly clean your dishwasher filters in warm, soapy water using an old toothbrush to ensure that they remain unblocked and effective. If your dishwasher uses hard water, soaking the filter in a bit of white vinegar can remove deposits from its holes.

Once a month or so, run a ‘cleaning cycle’ with no other dishes to blast away build-up before it becomes a problem. To do this, place a dishwasher-safe cup or bowl with white vinegar on your dishwasher’s upper rack and run a hot cycle. Then sprinkle a cup of bicarb soda along the bottom of your dishwasher and run a hot rinse cycle. The acidic vinegar and alkaline bicarb soda will break down scum, remove stains and absorb odours, keeping your dishwasher sparkling clean.


woman happily loading a dishwasher

With these tips and tricks, you'll be back to using your dishwasher in no time. Image: Getty

When should I call a plumber?

The earlier you call up a plumber to help unclog your dishwasher the better. Dishwashers use both water and electricity, so they can be dangerous to try and repair yourself. Always contact a plumber for an emergency blockage.

“A dishwasher is an electrical appliance, so you’ll need a specialist tradie to assist,” says Tayeh. “You can try to work through the step-by-step instructions above, but you may save a lot of time by calling up a professional. Many dishwasher clogs cannot be solved through DIY efforts.”

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