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How to clean your dishwasher

Get the best 'set and forget' performance from your machine with our expert's tips.

cleaning the drain of a dishwasher
Last updated: 28 October 2021
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We expect our dishwasher to last for more than 10 years, but if you don't take the time for a few minutes of maintenance then yours may not go the distance. 

Can't stand the thought of dishwasher maintenance? Our guide to buying a dishwasher tells you what to look for if you just want to replace it. For the rest of us, a little dishwasher TLC isn't too onerous. From removing odours and mould to general maintenance, here are our best tips to help you keep your dishwasher running trouble free.

How to clean a clogged dishwasher filter

If your dishwasher's not draining there's a good chance it's because the filter is blocked. Even if it's not, cleaning the filter is an important (if icky) part of your dishwasher routine, as grease and food scraps can collect in it, causing blockages, bad smells and other hygiene issues. Keeping your filter clean also helps your dishwasher run more efficiently and means food scraps are less likely to find their way deeper into the machine.

Modern dishwashers are designed for easy filter removal and cleaning, so there's really no excuse for putting it off any longer. 

  • First empty the dishwasher and remove the bottom basket – the filter will be in the sump, or lowest part of the dishwasher and should twist out without the need for tools (though you can always consult your manual if you get stuck).
  • Wash out the internal filter under hot running water, lightly scrubbing with a plastic brush to remove the grease and grime. The bigger trap filter can just be rinsed under hot water.
  • To replace the filter, simply reverse the removal process.

How to clean a mouldy dishwasher

A mouldy dishwasher isn't just gross, it can be seriously bad for your health. Because mould spores float around in the air, no home will ever be truly mould-free and the hot, moist insides of your dishwasher are the ideal environment for mould to grow.

While visible black spots or a musty odour coming from your dishwasher are clear signs of a mould problem, you may have mould issues and not even realise – many types of mould are tiny, colourless and odourless, so it's best to assume that there's mould lurking somewhere in your dishwasher, even if you can't see it.

  • To remove mould from your dishwasher, start by removing the racks and washing in hot soapy water. 
  • Next, wipe down the dishwasher's interior and around the door seal with a soapy sponge or washcloth. 
  • Refit the racks and let everything air dry thoroughly.
  • Next, use vinegar to kill the mould. Fill a dishwasher-safe container with a cup or two of vinegar and pop it in the rack with the lid off.
  • Run a hot cycle, with the dishwasher empty aside from your vinegar receptacle.
  • Now sprinkle a cup of baking soda into the dishwasher cabinet and run a second hot cycle.
  • Scrub any remaining mould with a toothbrush and soapy water, paying particular attention to sharp corners and around the door seal.

If vinegar's not cutting the mustard then you can bring out the heavy hitter in the form of chlorine bleach, which is a highly effective mould killer, and it removes mildew stains as an added bonus. Bleach is powerful stuff, so don't pour it directly onto rubber seals, remember to wear gloves, make sure your kitchen is well ventilated and never mix bleach with other chemicals, including the aforementioned vinegar, as it can create toxic gas.

To de-mould your dishwasher with bleach, follow the steps above for the dishwasher racks, then dilute 1 cup of bleach in four litres of water and scrub your dishwasher's insides with a stiff plastic brush (don't use a wire brush as it can damage your appliance), then use an old toothbrush to get into any sharp corners or behind the door seal (note that it may not kill mould that's penetrated deep into the porous surfaces of your seals). Next, run an empty cycle to rinse out any residual bleach.

Leave the door slightly ajar between cycles to allow air to circulate, which can help reduce the likelihood of mould returning.

What should you clean your dishwasher with?

You should use a soft, damp cloth or kitchen sponge to clean your dishwasher, and a plastic scrubbing brush and toothbrush to shift stubborn mould stains.

Never use a metal scourer or steel wool as these can damage the surfaces, and you can clean exterior surfaces with soapy water or an all purpose cleaner (but check your manual first). There are various cleaning agents suitable for use inside your dishwasher, including vinegar, bicarbonate of soda, chlorine bleach, citric acid or a variety of purpose made commercial dishwasher cleaners. Always check your manual for suggested cleaning agents and practices, and if you're using harsh chemicals, wear gloves and ensure your kitchen is well ventilated.

There are several commercially available cleaning products that claim to clear out your dishwasher's internals and leave it as good as new.

Running a cleaner through your dishwasher is a great way to flush away built-up grease and limescale, but unless you've let neglect get the better of you and you're now dealing with a decade's worth of grime in one go, you may better off with plain old white vinegar.

Vinegar pros

Like its commercial counterparts vinegar helps shift discolourations, foul smells, and nasties built up in your pipes, but has the added benefits of being less toxic, cheap and readily available.

Vinegar cons

Some dishwasher manufacturers, such as Miele, advise against using vinegar in their appliances as its acidity can potentially damage sensitive internals over time and recommend proprietary products designed for their machines instead. So check your manual first.

How to clean your dishwasher with vinegar

  • Pour two cups of vinegar into a bowl and place it in a rack in your otherwise empty dishwasher.
  • Give it a run, pausing the cycle in the middle for half an hour or so to give it an extra good soaking.
  • If the dishwasher still gives olfactory offence, throw in a generous handful of baking soda and run it again to give stubborn smells their marching orders.

Why pour the vinegar into a bowl and not just tip it straight in? Because many dishwashers run their drain pump at the start of the cycle to clear residual waste water left over from the last run, and this would pump your vinegar straight down the drain. Using a bowl bypasses this initial pump out and keeps the vinegar in the machine where it's needed.

How to clean a dishwasher that stinks

A dishwasher that's a bit on the nose isn't just unpleasant, it can be a sign of mould or harmful bacteria building up deep in its murky depths. It could also be a sign of grease and food particles lurking in the bottom of the machine.

The good news is any of the aforementioned cleaning techniques should solve the stinkiness at the same time, but if all you're worried about is offensive odours, then it's a quick and easy fix.

If your dishwasher's been sitting for a while with dirty plates in it then there's a good chance that's the source of the stench and all you need to do is actually run it. Normally we say wait until your dishwasher's completely full before you do but if it's getting whiffy then I think we can all agree the time has come.

However, if the bad smells don't disappear after running a cycle then you'll need to take steps to actively combat them.

  • First, remove the racks – these will only get in your way, and it's a good opportunity to give them a good scrub in the sink with hot soapy water.
  • Next up, clean the filter. Grease and food particles can build up rapidly in your filter, and no part of your dishwasher is more likely to be responsible for strange odours. See our detailed instructions for cleaning the filter above.
  • Now sprinkle a cup of baking soda into the bottom of the tub and let it sit overnight (baking soda is famous for absorbing nasty odours). Run a hot cycle the next morning and the baking soda should have removed any remaining odours.
  • Finally, check the drain hose for obstructions – blockages or restrictions can cause dirty water to pool instead of draining away, which could be the source of offensive smells. Water pooling in the bottom of your dishwasher is a sign that the drain hose may need some attention. You may need to remove your dishwasher from your cabinetry and detach the drain hose from the drain under the sink to access it. If you can fully remove your drain hose from your dishwasher it should be easy to see any blockages, which you can clear with the garden hose or a long thin stick.

How to clean spray arms on a dishwasher

If your dishwasher's not cleaning as well as it used to, a blocked spray arm could be the culprit. Over time, grime can become lodged inside the jets (particularly if you don't clean your filter regularly), making them less effective. Cleaning them may go a long way towards restoring lost performance.

To clean the spray arm jets, remove the spray arms and poke a toothpick or other soft, pointy object into the water exit holes to clear any obstructions and keep them flowing freely. Don't use sharp metal objects as it can damage the spray arms. Then, reinstall the spray arms.

How to clean the outside of a dishwasher

This not only keeps your kitchen looking spick and span, it helps keep corrosion at bay. Clean your dishwasher's door and fascia with a soft cloth and hot soapy water (or an all-purpose cleaner, but check your manual first), paying attention to corners, handles and around the controls. Glass cleaner works wonders on grime and fingerprints on stainless steel. For fully integrated appliances, clean the fascia as you would the rest of your cabinetry.

While not strictly outside the dishwasher, your door seals should also get a wipe down with a soft damp cloth – this helps keep mould and foul odours at bay, and clears away any obstructions which could lead to the door not sealing properly.

How to maintain a dishwasher with hard water

Hard water is water with a high concentration of minerals such as calcium and magnesium, and it's detrimental to dishwashers, reducing detergent effectiveness and causing hazy clouding on glassware over time. Worse, using very hard water can damage the dishwasher itself.

The good news is water in Australia is relatively soft, but mineral concentrations do vary from region to region.

If your home has hard water you should increase the amount of detergent you use, and use rinse aid to boost washing performance. You should also run a cleaner/descaler thorough your dishwasher regularly, or whenever you notice a build-up of limescale deposits. Since most build-up is chemically basic, you need to use an acid to remove it. The simplest options are vinegar or citric acid, or you can use a commercial product.

You should also take preventative measures to reduce the impact of hard water on your dishwasher. The simplest solution, aside from regular descaling, is to switch to a detergent with a water softener.

A more permanent solution is to install a water softener in your home. Water softeners can demineralise and soften hard water, which is good for your washing machine, sinks, showers and sprinklers as well as your dishwasher.

How to regularly maintain your dishwasher

Daily

  • Scrape and go. Scraping large particles into the bin or compost means you won't have to pick them out of the filter later, but there's no need to rinse plates before racking them (rinsing can even fool your dishwasher's automatic mode into thinking your crockery's cleaner than it is, so it won't wash as well).
  • Leave the door ajar. This isn't always practical, but it helps extend the life of your door seals, and circulating air helps keep mould and odours at bay. Some models even open automatically to aid drying performance.
  • Use good quality dishwasher detergent. Not only will they do a better job, quality cleaners are less likely to leave detergent residue behind and help prevent slimy deposits from building up in your appliance.

Weekly

  • Clean your dishwasher seals. Grime build-up around seals causes them to deteriorate more quickly. Run a damp cloth over door seals and contact points to keep them in top condition.
  • Clean the filter. A filter full of food scraps and grease will be the source of most dishwasher problems, so giving it a clean is essential to dishwasher health.

Monthly

  • Give the exterior a once-over. This not only keeps your kitchen looking spick and span, it helps keep corrosion at bay.
  • Fill the rinse aid dispenser. Topping up the reservoir next to the detergent dispenser will help keep your glasses streak-free. Many dishwasher tablets include their own rinse aid, but it's extra important if you prefer powders.
  • Run your dishwasher regularly. Dishwashers like frequent use, and leaving them to sit for too long can give fats and other deposits time to dry, harden and block pipes, allow seals to dry out, and may even contribute to insect infestation. Plus they're generally more water- and energy-efficient than hand washing, so using the dishwasher more will save you money as well as time.

Annually

  • Run the dishwasher on its hottest cycle while empty. Or better yet, give it a clean with a bowl of vinegar or a commercial cleaner. This helps flush grease, limescale and deposits out of the pipes and removes foul odours.
  • Check the spray arms. Clearing any blockages can restore lost dishwasher performance.

Can you really clean a dishwasher with Tang?

The '70s called and they want their sugary fluoro orange astronaut drink back. Well you might just want to hang onto that 25-year out-of-date jar in the back of the cupboard for a little longer, as we're hearing rumours that it makes for a pretty decent dishwasher cleaner.

While it sounds a little far-fetched, and we must admit we haven't tried it ourselves, there may be a bit of truth to it, as Tang is high in citric acid, which does do a decent job of cleaning your dishwasher, particularly if the problem is limescale build-up from repeated running with hard water.

According to a series of websites which all seem to quote each other, you should start a new cycle with your dishwasher empty, then after a couple of minutes, tip a tub of Tang in and let the dishwasher do its thing.

Like aspic dinner parties and other retro throwbacks Tang's increasingly difficult to come by, in Australia at least, but so if you've got some sitting around you've got nothing to lose by trying it, or you can put it to work with one of Tang's other uses, like making a variety of things orange, or causing diabetes.

Even more advice

  • Your dishwasher's manual will also give you the basic steps to help you get the longest life and best performance from your machine.
  • If you're experiencing problems with your dishwasher, check out our dishwasher troubleshooting guide.
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