Symptoms
- Sour or musty smell when opening the door
- Smell noticeable even right after a cycle
- Greasy film visible in the tub or on the door seal
- Odor seems to come from the drain area
Likely causes
- CommonClogged or dirty filterFood particles trapped in the filter rot and cause odor, especially if not cleaned in months.
- CommonGrease and food buildup in the tub or spray armsHard water and grease combine to coat interior surfaces where bacteria grow.
- PossibleStanding water in the drain hose or sumpA partial drain clog leaves stagnant water that develops a sour smell.
- PossibleMoldy door gasketThe rubber seal traps moisture and food residue, encouraging mold growth.
- Less commonGarbage disposal or drain line backupIf the dishwasher shares a drain line with a smelly disposal, odor can travel back into the tub.
What to do
- Remove the bottom rack and take out the filter; rinse it thoroughly under hot water, scrubbing off any trapped debris.
- Wipe down the door gasket and the underside of the door with a damp cloth and mild cleaner, checking for mold spots.
- Run an empty cycle with a cup of white vinegar in a bowl on the top rack, or use a dishwasher-specific cleaner.
- Check the spray arm holes for grease buildup and clear them with a toothpick if needed.
- Run the kitchen disposal and flush it if the dishwasher drains through it, since disposal odor can migrate into the tub.
- Leave the dishwasher door cracked open between uses so the interior can air out and stay dry.
- If odor returns quickly after cleaning, check for a partial drain clog or standing water in the hose.
Tools and parts
- Old toothbrush
- White vinegar
- Damp cloth
Dishwasher cleanerSearch: “dishwasher tub cleaner tablets”
When to call a pro
If the smell persists after a full cleaning and the drain runs clear, have a technician check for standing water in the sump or a drain line issue.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.