Opening your dishwasher and noticing an odor can make even freshly washed dishes seem less than clean. If your dishwasher smells bad, the source may be something relatively manageable, such as trapped food residue, or it may point to a drainage, drying, or mechanical problem that needs professional attention.
Understanding what causes dishwasher odors can help you pinpoint the source of the smell and determine the best way to address it.
Common Causes When a Dishwasher Smells Bad
If your dishwasher smells bad, persistent dishwasher odors should not be masked or ignored, as it may point to residue buildup or a performance issue. Food particles, grease, detergent, and moisture can collect inside the appliance and create unpleasant smells over time.
Start by checking these common reasons your dishwasher smells bad and what each one can tell you about the source of the odor.
Food Debris Is Trapped in the Filter
Many dishwashers have a filter designed to catch food particles before they circulate through the appliance. Over time, residue can collect around the filter and begin to smell, especially when it remains damp between wash cycles.
Food debris in this area can contribute to sour, musty, or rotten odors. The smell may become more noticeable when the dishwasher heats up during a wash cycle. If your dishwasher smells bad shortly after running, buildup around the filter may be one of the first areas worth checking.
Common signs of filter-related buildup can include:
- A sour or stale odor when the dishwasher door is opened
- Visible food particles near the bottom of the dishwasher
- Residue collecting around an accessible filter
- Dishes coming out with small particles or debris
- Odors becoming stronger after a wash cycle
If your dishwasher has a user-removable filter, follow the cleaning guidance in the manufacturer’s owner’s manual.
If the filter appears clean but the odor continues, another part of the dishwasher may be contributing to the problem.
Food and Grease Have Built Up Inside
Even when dishes are scraped before loading, small amounts of grease, sauce, food particles, and detergent residue can remain inside the dishwasher. Over time, buildup may collect on interior surfaces and create an unpleasant smell.
Areas that may collect accessible residue include the interior walls, door edges, racks, and the bottom of the tub. Moisture can make this buildup more noticeable because bacteria and mildew tend to thrive in damp environments.
Watch for signs such as:
- A greasy film on accessible interior surfaces
- Discoloration or residue around the door area
- A stale smell that develops between wash cycles
- Odors that remain even after dishes are removed
- Visible food buildup near the bottom of the tub
Wiping accessible interior surfaces and following the manufacturer’s recommended cleaning procedures can help control buildup. Only use cleaning products approved for your dishwasher model.
If regular cleaning does not improve the smell, the odor may be coming from a drainage issue or another part of the dishwasher that requires professional diagnosis.
Standing Water Remains After a Cycle
When a dishwasher is operating properly, most of the wash water should drain away at the end of the cycle. Some models may retain a small amount of water in specific areas, but noticeable dirty water remaining in the tub can indicate a drainage problem.
Standing water can quickly develop an unpleasant odor because it may contain grease, food residue, and detergent from the previous wash.
Possible warning signs include:
- Visible water remaining at the bottom after the cycle ends
- Cloudy or dirty-looking water
- A sewage-like or stagnant odor
- Dishes remaining unusually wet
- Food residue remaining after washing
- Unusual sounds during the draining portion of a cycle
If a significant amount of water remains after a completed cycle, a technician should inspect the dishwasher. The problem may involve the drainage system or another component that requires professional diagnosis.
There Is a Drainage Problem
A dishwasher does not always need to have a large pool of standing water for a drainage problem to be present. Water may be draining too slowly or may not be leaving the appliance as effectively as it should.
When dirty water remains within parts of the drainage system, odors can develop and return every time the dishwasher runs.
Symptoms that may accompany drainage concerns include:
- Recurring unpleasant smells
- Water remaining after a cycle
- Slow drainage
- Unusual noises when the dishwasher drains
- Food residue left on dishes
- Odors that return shortly after cleaning the interior
Drain pumps and other drainage components can involve electrical and mechanical parts. These areas should be inspected by a professional rather than disassembled by the homeowner.
If a pump or related assembly has failed, a qualified dishwasher repair technician can determine whether replacement is necessary.
Excess Moisture Is Lingering Inside
Dishwashers naturally contain some moisture after washing, but excessive moisture that remains for long periods can contribute to musty odors. A dishwasher that does not dry effectively may stay damp enough for smells to develop between cycles.
Drying performance can be influenced by loading practices, cycle selection, rinse aid use, or a malfunction involving the appliance’s drying system. If you have a dishwasher not drying properly, issues with moisture removal may also contribute to lingering odors inside the appliance.
Signs that excessive moisture may be contributing to odors include:
- Dishes staying unusually wet after a completed cycle
- Water droplets remaining throughout the interior
- A musty smell when the door is opened
- Moisture remaining long after the cycle has finished
- Odors becoming more noticeable between uses
Check that you are using the appropriate cycle and following the manufacturer’s recommendations for loading and rinse aid. If drying performance continues to decline, a professional can determine whether a heating, fan, sensor, or other internal component is contributing to the problem.
The Dishwasher Is Not Used Regularly
Dishwashers that sit unused for extended periods can sometimes develop stale or musty odors. Small amounts of moisture and food residue may remain inside the appliance even after the previous cycle has ended.
When the dishwasher is not used frequently, that residue has more time to produce noticeable smells.
You may notice:
- A stale smell after the dishwasher has not been used for several days
- Musty odors when first opening the door
- Residue on accessible interior surfaces
- Odors that improve temporarily after the dishwasher is used
- Smells that gradually return during periods of infrequent use
Keeping accessible areas clean and following the manufacturer’s recommended maintenance schedule can help reduce odor buildup.
A manufacturer-approved dishwasher cleaning product may also be appropriate if it is recommended for your specific model.
If the odor returns frequently despite normal use, it should be evaluated by a professional.
A Component Is Overheating
Not every unpleasant dishwasher smell comes from food, grease, or standing water. A burning, electrical, or melting-plastic smell should be treated differently from a typical stale or musty odor.
Dishwashers contain heating elements, wiring, controls, motors, and other electrical components. If one of these parts malfunctions or overheats, it may produce an unusual smell.
Warning signs that deserve prompt attention include:
- A burning or electrical odor
- The smell of melting plastic
- Visible scorching or discoloration
- Smoke coming from the appliance
- Unusual noises occurring with the odor
- A smell that becomes stronger while the dishwasher is operating
If you notice a burning smell, smoke, melted material, or visible scorching, stop using the dishwasher and schedule professional dishwasher repair service.
Do not remove panels, access wiring, or attempt electrical testing. A trained technician should inspect the appliance and determine whether an electrical or mechanical component has failed.
When to Call for Professional Dishwasher Service
A dishwasher odor caused by minor food or detergent buildup may improve with routine cleaning. However, persistent smells can point to standing water, poor drainage, inadequate drying, or a malfunctioning internal component.
Professional service may be needed if the odor continues after cleaning or occurs alongside other symptoms, such as water remaining after a cycle, unusually wet dishes, abnormal sounds, weak cleaning performance, or a burning smell. These warning signs may indicate a problem that requires proper diagnosis rather than additional cleaning.
If your dishwasher continues to smell or shows other signs of trouble, contact the Baton Rouge dishwasher repair experts at Solar Refrigeration & Appliance Service for professional diagnosis and repair.
