Dishwasher Smells Bad: The Filter You Did Not Know You Had
Most dishwashers have a filter that traps food sludge, and most owners have never cleaned it, because many manuals barely mention it. That filter is the smell, nine times out of ten.
The short answer
Pull the bottom rack, twist out the filter at the tub floor, and scrub it in the sink: that is the smell, and it costs nothing. Then run an affresh Dishwasher Cleaner tablet on an empty hot cycle for the buildup you cannot reach. The tablets hold 4.6 stars from about 67,000 ratings on Amazon (November 2026).
Why does this happen?
A dishwasher does not drain perfectly. Each cycle leaves a film of food particles, grease, and mineral residue in the sump, the spray-arm nozzles, and above all the filter, a mesh cylinder or screen at the bottom of the tub designed to catch debris before it recirculates. Trapped organic matter in a warm, damp, dark box decomposes, and the smell greets you when you open the door.
Many owners never learn the filter exists because some brands market their machines as filter-free (those use a grinder instead, and smell less for this reason) and because the filter hides under the bottom rack. Locating yours is model-specific: cylinder in the center or a flat screen under the spray arm. Your manual's diagram, searched by model number, settles it in a minute.
The fix, in order
The steps are ordered cheapest first. Stop at the one that solves it and skip the rest; the product is there only for where the free steps run out.
Free step
Find and scrub the filter
Bottom rack out, filter twisted or lifted out per your model, scrubbed under hot water with a brush and a drop of dish soap, and the sump wiped clean. Replace it firmly; a loose filter lets debris into the pump.
Free step
Clear the spray-arm holes
Check the nozzles for seeds, glass slivers, and mineral crust; a toothpick clears them. Blocked arms cause both patches of smell and badly washed top racks.
The product step
Run the affresh cycle
One affresh Dishwasher Cleaner tablet in the detergent cup, empty machine, hottest cycle. It cleans the tub walls, the internal lines, and the limescale the filter scrub cannot reach. Do this monthly in a hard-water home, or in a home that uses the machine a lot.
The product for this step
affresh Dishwasher Cleaner tablets
Habit step
Leave the door cracked between loads
If you keep the door closed, the damp inside brings the smell back between washes. Leaving the door ajar and keeping the filter dry is all you need to prevent it.
The evidence, in tiers
Tier 1 · The method
Filter maintenance is the manufacturers' own first instruction for odor complaints. The method here is the manual for your model, and this guide tells you how to find it rather than guessing.
Tier 2 · This product
affresh Dishwasher Cleaner holds 4.6 stars from about 67,000 ratings on Amazon (November 2026).
We have not pulled the filter on a test machine for this guide. The steps follow manufacturer maintenance documentation across the major brands.
Tier 3 · What owners report
The most common owner report is disbelief at what is in the filter, followed by the smell ending immediately. That pattern confirms that the filter was the cause.
The alternatives, conceded where they win
| Option | What it is | The honest verdict |
|---|---|---|
| affresh Dishwasher Cleaner | Empty-cycle tablet for tub, lines, and scale | The pick for step two: it cleans where hands cannot reach, after the free step does the main work. |
| Vinegar in a bowl on the top rack | Acid rinse trick | Wins on price for light, fresh odor; it loses on grease and scale in the lines, and it never touches the filter, which is the actual source. |
| A new dishwasher | Replacement | Only worth it when the pump or seals have failed. For a smell on a working machine, it means spending $500 when the filter only needed a scrub in the sink. |
The honest price comparison
Compare it with a service call at $100 to $200, where the technician tells you to clean the filter — a story appliance technicians tell constantly. After the free scrub, a tablet box at about $10 is all you need.
Where it falls short
The weaknesses below come from the product's own review record, the same record the recommendation rests on.
- It cannot fix a drainage or venting fault; sewage smells persist until the plumbing is right.
- On machines with grinder systems and no filter, the tablet does all the work and there is no free step, so expect the tablet to do everything on those machines.
- Neglected filters can be fragile with age; scrub gently or a cracked replacement becomes part of the bill.
The product, in short
affresh Dishwasher Cleaner tablets
Questions people ask next
Where exactly is the filter?
Under the bottom rack, at the tub floor: either a central cylinder you twist counterclockwise, or a flat screen under the lower spray arm. Your model number plus the word filter finds the diagram in a minute.
How often should the filter be cleaned?
Monthly in most homes, more often if you load unrinsed dishes. If the smell returns, it is time to clean the filter again.
The smell is like rotten eggs. Same page?
No. A rotten-egg or sewage smell points to a drainage problem: check the high loop in the drain hose and the garbage disposal connection first. Nothing on this page is a substitute for that fix.
Can I run vinegar and a tablet together?
No need and no benefit; they are different tools for different buildup. Use the tablet cycle as directed and keep vinegar for the kettle.
Manufacturer maintenance documentation on dishwasher filters and odor · Amazon product record for affresh Dishwasher Cleaner (November 2026)
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