How to Clean a Dishwasher

It feels a little unfair that the machine responsible for clean plates can end up being one of the grubbiest corners of the kitchen. Food scraps, grease and minerals from hard water slowly settle in places you never see while loading the racks. The first signs are usually subtle: glasses come out with a faint film, a musty smell drifts out when the door opens, or small bits of debris cling to cups that should be spotless.

The good news is that a thorough clean takes less than an hour, most of it waiting time, and needs nothing more exotic than warm water, a soft brush and a couple of cupboard basics. Before starting, flick through the manual for your model. Manufacturers differ on which parts lift out and which cleaners they approve, and their advice always beats a general guide like this one.

What to gather first

• An old toothbrush or a soft bottle brush
• A non-scratch sponge and a microfibre cloth
• Washing-up liquid and a bowl of warm water
• White vinegar or a dishwasher cleaner your manual allows
• Baking soda for odours (optional)
• A toothpick or wooden skewer for clogged holes
• Rubber gloves, because the filter is rarely pleasant

Step one: empty it and switch it off

Unload every rack and pull the lower basket right out so you can see the floor of the tub. If your model has a dedicated power switch or plug, turn it off. You will be reaching into the base, and it is sensible to make sure nothing can start while your hands are inside.

Step two: tackle the filter

The filter is the part that matters most, and the one most people have never touched. On many machines it sits in the base under the lower spray arm and twists out with a quarter turn. Some have a coarse outer screen plus a finer mesh cylinder; others combine the two.

Lift it out and rinse it under a warm tap. Use the brush on the mesh with gentle strokes, working from the inside outwards so trapped particles fall away rather than being pushed deeper. A drop of washing-up liquid helps lift grease. Look into the opening where the filter sat and scoop out any loose bits, such as fruit stickers, broken glass or seeds, before refitting it firmly. A filter that is not locked into place can let debris reach the pump.

Step three: clear the spray arms

Spray arms rotate during a cycle and push water through rows of tiny holes. When those holes clog, parts of each rack simply stop getting washed. Most arms unclip or unscrew; check the manual for the release method. Hold each arm up to the light and look through the holes. Poke out any blockage with a toothpick, then flush the arm under running water and shake it to hear whether anything is still rattling inside.

Step four: wipe the door, seals and corners

The rubber gasket around the door collects a surprising amount of grime, especially along the bottom edge where drips gather. Wipe it with a cloth dipped in soapy water, then go over the inside of the door, the detergent dispenser and the hinges. A toothbrush gets into the ridges along the lower lip of the door, a spot that is often responsible for that stale smell.

Step five: run a cleaning cycle

With the machine empty and the filter back in place, you can freshen the interior and loosen mineral scale. Two common approaches are shown below. Pick one, not both at once, and follow your manual if it recommends a specific product.

Method	How to do it	Best for
Vinegar cup	Place a dishwasher-safe cup of white vinegar upright on the top rack and run a hot cycle with nothing else inside.	Cloudy film and light limescale
Baking soda sprinkle	Scatter a small handful across the floor of the tub and run a short hot rinse.	Lingering odours
Dedicated cleaner	Use exactly as the packet and your manual describe.	Heavier build-up, or when the manual advises against vinegar

If you try both vinegar and baking soda, run them on separate days. Mixed together they simply fizz and cancel each other out.

When the problem keeps coming back

Sometimes cleaning improves things only briefly. Standing water in the base after a cycle, a strong drain smell that returns within days, or dishes that are still gritty after a careful clean can point to a blocked drain hose or a pump issue. These are worth a call to a qualified technician rather than further home experiments. If you notice water seeping under the cabinet, our piece on early leak alerts and water damage explains why acting quickly pays off.

Habits that keep it fresher

1. Scrape, do not rinse. Knock leftovers into the bin but skip the full pre-rinse; many detergents work better with a little food to act on.
2. Check the filter regularly. A quick look every week or two prevents the big, unpleasant clean-out.
3. Leave the door ajar after a cycle. Letting steam escape helps the interior dry and discourages musty smells.
4. Keep the salt and rinse aid topped up if your machine uses them, particularly in hard-water areas.

A clean dishwasher also tends to use its water more effectively, which ties into the wider picture of a thrifty, efficient kitchen. For more on that side of home upkeep, see how plumbing services support water and energy savings. Give your machine this attention every month or so, and it should keep returning the favour with sparkling glasses.