Why Your Dishwasher Smells Bad
A dishwasher is designed to clean, but over time it can become a breeding ground for bacteria and foul odours. A smell of rotten eggs or damp mould indicates that food debris and grease have become trapped in the hidden crevices of the machine.
Where Odours Hide
Dishwashers do not have a food disposal unit. Any solid food washed off plates ends up in the base filter. If not cleaned regularly, this food rots in the warm, damp environment. Additionally, grease coats the inside of the drainage hoses and the hollow spray arms, creating persistent smells.
Common causes
- Rotting food debris trapped in the main base filter
- Grease and fat buildup inside the hollow spray arms
- Stagnant water sitting in the drain hose due to poor plumbing
- Black mould growing on the rubber door seals
- Exclusively using low-temperature "Eco" washes
Safe first checks
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Safety warning
Always ensure the dishwasher is empty of dishes before using a chemical dishwasher cleaner, as the high concentration of cleaning agents can damage glassware and cutlery.
When to stop and call a professional
If you have thoroughly cleaned the machine but it still smells like sewage, the drain hose may be plumbed incorrectly, allowing dirty sink water to siphon back into the appliance. A plumber or appliance engineer can correct this.
How this information is researched
Publisher: Error Code Lookup Editorial Team. Error Code Lookup is an independent appliance-information resource and is not affiliated with appliance manufacturers. Guidance is written in our own words and reviewed with safety boundaries in mind.
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Frequently asked questions
Why do Eco washes cause smells?
Eco washes use lower temperatures (around 45-50°C) to save energy. These temperatures are not hot enough to melt away animal fats, which eventually coat the inside of the machine and rot.
Should I rinse plates before loading?
Scrape solid food into the bin, but do not pre-rinse plates under the tap. Dishwasher detergent needs grease to cling to; without it, the detergent foams excessively and can damage the machine.
Why is there water left in the filter?
A small amount of clean water under the filter is normal and prevents the pump seals from drying out. If the water is murky and smells, the drain hose may be blocked.