How to unclog a dishwasher

Unclogging your dishwasher: everything you need to know

Is my dishwasher clogged?

“Sometimes it can be fairly obvious when your dishwasher is clogged,” says Nathan Tayeh, RACV Homes Trades & Services Senior Product Manager.

“You might see an error message on the dishwasher's display, or spot water all over your kitchen floor. You may also notice grimy water sitting in the bottom of your dishwasher or discover that your dishes are still dirty after a cycle.”

Dishwasher users might also 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. Dishwasher blockages can also be caused by dislodged machine parts, and even children's toys.

Large food scraps are usually the culprit of dishwasher clogs in the home. Image: Getty

How can I unclog my dishwasher?

Before calling a plumber, there are several quick and easy steps to follow to try and fix a minor dishwasher clog.

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 natural 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 filter a thorough clean with warm, soapy water to remove any debris. Make sure to wipe out any debris in the area before replacing it.

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.

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

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

How can I prevent dishwasher clogs?

To help prevent future dishwasher clogs, make sure to scrape large food particles off your dishes before loading them in for cleaning. That said, you should also refrain from thoroughly rinsing your dishes before loading them into your dishwasher. Clean dishes 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 help remove deposits from its holes.

Once a month, 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 help break down scum, remove stains and absorb odours, keeping your dishwasher sparkling clean.

Watch Chelsea Smith highlight the biggest common mistakes people make in the kitchen.

When should I call a plumber to unclog a dishwasher?

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.”