How to Deep Clean Dishwasher: Step-by-Step Guide (2026)

To deep clean a dishwasher, remove and wash the filter, scrub the spray arms, wipe the door seals, and run an empty hot cycle with white vinegar followed by a sprinkle of bicarbonate of soda. This clears trapped food, grease, smells, and limescale, and it takes about 30 minutes of hands-on time. The steps below walk you through the whole process.

How to Deep Clean Dishwasher: Step-by-Step Guide

A dishwasher that smells musty, leaves food bits on plates, or comes out cloudy needs a proper deep clean. Most experts say you should do a full deep clean every month or two, and it is especially important in hard-water areas like London, where limescale builds up fast. Set aside half an hour and gather your supplies first.

What you will need:

• White vinegar (distilled is best)
• Bicarbonate of soda (baking soda)
• Washing-up liquid
• An old toothbrush or small brush
• A soft cloth or sponge
• Rubber gloves

Step 1: Empty the Dishwasher and Remove the Filter

Start with an empty dishwasher. Take out the bottom rack so you can reach the drain area easily. At the bottom of the tub, you will find the filter. It usually twists out with a quarter turn, though the exact method depends on your model. Check the manual if you are unsure.

The filter is almost always the main cause of bad smells. Food, fat, and grit collect there, and because it sits in standing water, it goes unpleasant fast. Pull out the filter and any parts that come with it, and you may well find a layer of grey sludge. That is normal, but it is also why a deep clean dishwasher session matters.

Step 2: Wash the Filter in Hot Soapy Water

Wash the filter in the sink with hot water and washing-up liquid. Use the toothbrush to scrub into the mesh and the edges, getting into every corner where food sticks. Rinse it well under the tap.

If the filter has stubborn grease or a whitish limescale coating, soak it in a bowl of warm water with a cup of white vinegar for 20 to 30 minutes, then scrub again. The vinegar cuts through both grease and scale without harsh chemicals. Do not use bleach or abrasive scouring pads on the filter, as they can damage the mesh.

Step 3: Clean the Spray Arms

The spray arms are the spinning bars at the bottom and top of the dishwasher. Their little holes get clogged with food particles and limescale, which is why dishes sometimes come out dirty on one side only.

Most spray arms lift or twist off. Take them out, rinse them under the tap, and use a toothpick or pin to poke out anything blocking the holes. Shake them to check that water flows freely through the arms. If the holes are coated in white scale, soak the arms in vinegar for half an hour, as you did with the filter.

Step 4: Wipe the Door Seals and Edges

Dishwasher door seals are a favourite hiding place for grime. Pull the seal gently back with your fingers and wipe along it with a damp cloth dipped in hot soapy water. You will often find a line of dark gunge, especially along the bottom edge of the door.

Also wipe the edges of the door, the corners of the tub, and the area around the latch, places the spray arms never reach. For stubborn mould on the seals, dip your toothbrush in vinegar and scrub carefully, then wipe clean.

Step 5: Run an Empty Hot Cycle with Vinegar

Put the filter and spray arms back in. Place a dishwasher-safe bowl or mug filled with about 250ml of white vinegar on the top rack. Run the hottest cycle your dishwasher offers, usually labelled intensive or 70°C.

The hot vinegar loosens grease, breaks down limescale, and kills the bacteria that cause bad smells. The Which? guide to cleaning a dishwasher recommends this kind of regular maintenance cycle to keep your machine working well. Do not add any detergent for this cycle, just the vinegar.

Step 6: Follow with a Bicarbonate of Soda Cycle

When the vinegar cycle finishes, open the door and sprinkle about 100g of bicarbonate of soda across the bottom of the tub. Run a short hot cycle, again with nothing else inside.

The bicarb acts as a gentle abrasive and deodoriser. It lifts any remaining stains, brightens the inside of the tub, and leaves the dishwasher smelling fresh. The combination of vinegar then bicarb tackles both grease and odour in a way that detergent alone cannot.

Dealing with Limescale in Hard-Water Areas

London water is very hard, which means limescale is your dishwasher’s biggest enemy. If the inside of your dishwasher has a white, chalky coating, or your glasses come out cloudy, limescale is the cause.

The vinegar cycle handles light limescale, but heavy build-up needs more help. Use a proper dishwasher cleaner such as Finish Dishwasher Cleaner once a month, which is made for hard water. Check your salt reservoir too: most UK dishwashers have a salt compartment in the base, and filling it with dishwasher salt softens the water and reduces scale. The Southern Water hard water guide confirms that London and much of the South East have some of the hardest water in the country.

Products like Finish In-Wash cleaners and Hob Brite-style specialist cleaners are sold in Tesco, Sainsbury’s, and Wilko, and they make the monthly maintenance cycle easy. A quick wipe of the heating element area with vinegar also helps in very hard water.

Cleaning the Outside and the Drain

While the maintenance cycles run, clean the outside. Wipe the front panel with a damp cloth and a little washing-up liquid, and pay attention to the buttons and handle, which collect fingerprints and grease. For stainless steel fronts, wipe in the direction of the grain to avoid streaks.

Check the drain at the bottom of the tub. Lift out the filter and look into the drain area for bones, glass shards, or bits of food. Fish them out with a paper towel, wearing gloves, so they do not block the pump.

Top Tips

• Scrape plates before loading, but do not pre-rinse. Modern detergent needs something to cling to, and a little food helps the cleaning work.
• Run a maintenance cycle with vinegar or a dishwasher cleaner once a month, especially in hard-water areas like London.
• Keep the dishwasher salt topped up. It stops limescale on the heating element and cloudy glassware.
• Leave the door slightly open after each cycle so the inside dries out and stays fresh.
• Clean the filter every week or two, not just during the monthly deep clean. It takes two minutes.

Common Mistakes to Avoid

• Using bleach to clean the dishwasher. It can damage the rubber seals and stainless steel interior.
• Running the vinegar cycle with detergent in the machine. Use vinegar on its own.
• Ignoring the door seals. Smells often come from the seals, not the inside of the tub.
• Forgetting the salt reservoir in hard-water areas, then wondering why the glasses are cloudy.

How often should you deep clean a dishwasher?

A full deep clean once a month is ideal, and every two months at the least. If you notice smells, dirty dishes, or cloudy glasses, clean it straight away. The filter itself deserves a quick rinse every week or two.

Can you use vinegar and bicarb together in the dishwasher?

Yes, but run them in separate cycles, not at the same time. The vinegar goes in first on a hot empty cycle to cut grease and limescale, then the bicarb goes in for a second cycle to deodorise and brighten. Mixing them together in one go just neutralises both.

Why does my dishwasher smell even after cleaning?

The smell is usually trapped in the door seals, the filter housing, or the drain area. Take the filter out and scrub the housing underneath it with vinegar, wipe deep inside the door seal folds, and leave the door ajar after cycles. If the smell persists, check the drain hose for a kink that is trapping dirty water.

Do I need a special dishwasher cleaner?

Vinegar and bicarb do most of the work for free, but a dedicated product like Finish Dishwasher Cleaner is worth using once a month in hard-water areas. It is designed to reach the hidden parts, like the heating element and pipework, that a home remedy cannot fully clear. The Energy Saving Trust’s appliance advice has more tips on keeping your appliances running efficiently.

A deep-cleaned dishwasher washes better, smells fresher, and lasts longer. Once you have done the full routine, a monthly vinegar or cleaner cycle and a weekly filter rinse will keep it in great shape with very little effort.