There is a particular family moment when someone unloads the dishwasher, holds a glass up to the light, and says the thing you were hoping nobody would notice. Cloudy. Slightly gritty at the rim. A plate that came out with a fleck of yesterday's rice welded on. And underneath it all, when you open the door on a cold morning, a smell that is not quite anything but definitely not clean.
None of this means the machine is finished. It almost always means the dishwasher has been quietly cleaning your kitchen for two years while nobody cleaned the dishwasher. It takes about twenty minutes to put right, mostly in short bursts while you're in the kitchen anyway.
Start at the bottom: the filter
Pull out the lower rack and find the filter in the floor of the machine — usually a cylinder you twist a quarter turn to release, sitting in a flat mesh plate. Lift both out over the sink, and brace yourself, because the first time is genuinely grim. Rinse them under a hot tap, then work a soft brush and a drop of washing-up liquid into the mesh until water runs through freely rather than pooling. Hold the mesh up to the light; you should see light through it evenly.
While the filter is out, wipe the sump underneath with kitchen paper — that is where fragments of glass, olive stones and rogue labels collect. Anything hard left down there gets flung around the machine all cycle. Then seat the filter properly and twist until it locks. A filter that isn't clicked back in is a classic cause of a sudden drop in cleaning quality.
The spray arms and the door seal
Lift or unclip each spray arm — most come off by hand or with a gentle unscrew — and check every jet. Limescale and food debris block them, and a blocked arm means a whole section of the top rack gets barely rinsed. Poke each hole through with a cocktail stick or the tip of a paperclip, flush the arm under a tap until water sprays out of every hole, and refit it. Spin it with a finger afterwards to check it turns freely.
Then the door. The rubber seal around the frame is where the smell lives, because it never gets hot water and it stays damp. Wipe it with a cloth wrung out in hot soapy water, pulling the lip back gently so you get into the fold, and do the same along the bottom edge of the door and the lower lip of the cabinet, where a grey sludge collects. Finish with the detergent drawer and the little flap, which can crust over and stop opening fully.
The hot empty cycle — and the hard water question
Now run the machine empty on its hottest, longest programme. You can put a heatproof bowl of white vinegar on the top rack, or sprinkle a couple of spoonfuls of bicarbonate of soda across the floor of the machine and run it — just don't do both in the same cycle, because they neutralise each other and you get fizzy nothing. Vinegar is the better choice for limescale and film; bicarbonate is better for smell.
If your glassware still looks hazy after a proper clean, the culprit is usually water hardness rather than dirt. In hard-water areas, keep the salt reservoir topped up with dishwasher salt — actual dishwasher salt, not table salt — and set the water hardness level on the machine according to its manual. Keep the rinse aid topped up too, because that is what stops droplets drying into spots. And note that permanent etching on old glasses, which looks like frosting and doesn't change with cleaning, is not reversible; those glasses are better washed by hand from now on.
The weekly habits that stop it coming back
Three small things keep a dishwasher sweet. Scrape plates properly but stop pre-rinsing them spotless — modern detergents need something to work on. Rinse the filter under the tap once a week; it takes thirty seconds and prevents nine-tenths of the problem. And leave the door ajar for half an hour after the cycle finishes so the inside dries instead of stewing.
Add one full empty hot cycle a month to that list and you will more or less never think about this again. I keep it pegged to the same day I water the balcony pots, because a habit attached to another habit is a habit that survives a busy week.
How often should I clean my dishwasher?
Rinse the filter weekly, wipe the door seal and detergent drawer every couple of weeks, and run an empty hot maintenance cycle roughly once a month. If your machine runs twice a day for a big household, or you regularly wash very greasy roasting trays, move that maintenance cycle up to every two or three weeks. The spray arms only need checking every few months unless cleaning performance drops.
Why does my dishwasher smell even after a hot cycle?
Nine times out of ten the smell is coming from somewhere the hot water never reaches: the fold of the rubber door seal, the bottom lip of the door, or a filter that was refitted while still greasy. Clean all three by hand and leave the door open to dry after cycles. If the smell persists and water seems slow to drain, check that the drain hose isn't kinked behind the machine and give the sink waste it shares a hot flush — and if it still lingers, it's worth having an engineer look rather than adding more products.
