Dishwasher Smells? What Each Odour Means and How to Get Rid of It

A dishwasher should smell of nothing at all. When opening the door greets you with something fishy, eggy or swampy instead, the machine is telling you where old food and old water are hiding, and the smell itself is a surprisingly good diagnostic.

Why does my dishwasher smell is one of the most common questions we get on kitchen call-outs, and in most cases the fix is an afternoon of cleaning, not a repair. But one version of the problem is mechanical, and it is worth knowing the difference before you scrub everything twice and wonder why the smell keeps returning.

Here is what each smell means, the full de-stink routine, and the point where it stops being a hygiene job.

What the smell is telling you

Different odours have different sources, and it pays to sniff before you scrub.

• ✓Fishy or rotten food smell → decomposing scraps in the filter and sump, the most common cause by far
• ✓Eggy or sulphurous → trapped waste water, usually a drainage or drain-hose problem
• ✓Damp, musty towel smell → biofilm on the door seal and interior, a machine that never dries out
• ✓Burning or plastic smell → not an odour problem at all: something has fallen on the heater element, or a component is overheating — stop the machine and check

Step 1: Empty and scrub the filter

The filter in the floor of the tub catches everything that leaves your plates, and a fishy dishwasher smell is almost always a filter that has been quietly composting for months. Twist it out, rinse it under a hot tap, scrub the mesh with an old brush and detergent, and clean out the sump recess it sits in, where a film of greasy water lingers.

While you are down there, check the small amount of water in the sump looks clean. A little clear water is normal and by design. Grey soup is not, and points at drainage.

Step 2: Clear the spray arms and wipe the seals

Food fragments lodge in the spray arm jets and rot in place, and the door seal, especially the lower lip, collects a black biofilm exactly like a washing machine’s. Poke the arm jets clear, then wipe the full circumference of the door seal with hot soapy water or a 50/50 vinegar mix, getting into the fold at the bottom where the door meets the tub. That lower lip is the single most missed spot in the machine.

Step 3: Run a hot empty cycle with vinegar or a machine cleaner

With the mechanical grot gone, finish chemically: a cup of white vinegar in a bowl on the top rack, hottest cycle, empty machine. It dissolves the grease film that carries smell through the whole interior. A branded dishwasher cleaner does the same with added descaling, worth it in Perth’s harder-water suburbs.

How to get rid of smell in a dishwasher long-term is then mostly habit: scrape plates, run the machine at least every couple of days, leave the door ajar after cycles so the interior dries, and give the filter a monthly rinse. Our guide to a dishwasher that is not cleaning properly covers the same maintenance from the performance side.

When the smell keeps coming back: the drainage problem

If a full clean buys you a week of freshness and then the eggy smell returns, stop scrubbing, because the problem is standing waste water, not hygiene. Three usual causes:

First, a drain hose without a high loop, which lets sink waste water siphon back into the machine between cycles. Second, a partial blockage in the hose or sump keeping dirty water in the machine, the early stage of the fault we cover in our dishwasher not draining guide. Third, a drain hose connected to the sink waste without the proper spigot arrangement, sharing air with the drain and its smells.

All three are plumbing-and-parts jobs a technician sorts quickly, and no amount of vinegar fixes them.

The burning smell exception

A dishwasher that smells of burning plastic or scorched metal is a different conversation. Usually it is a plastic item, a lid, a chopping board, a utensil, that has dropped through the racks onto the exposed heater element, and you will find the melted evidence. Remove it, air the machine, and the smell fades over a few cycles.

If there is nothing on the element and the burning smell persists or comes with cutting out, stop using the machine and book it in. Motors and elements that overheat do not improve on their own.

CAI Appliance Services has repaired dishwashers across Perth for over 25 years, and we are the authorised service agent for several major brands including Bosch, Miele, Smeg and Blanco. Details on our dishwasher repair page.

Dishwasher smells: the quick version

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