Why Does My Dishwasher Smell? Causes and How to Fix It

There's nothing more frustrating than opening your dishwasher and being hit with a foul smell — especially when it's supposed to be cleaning things. The good news: dishwasher odors are almost always caused by one of a handful of fixable problems. Here's how to diagnose and eliminate the smell for good.

Common Causes of Dishwasher Smell

1. Clogged or Dirty Filter

This is the #1 cause of dishwasher odors. The filter traps food particles — when it's not cleaned regularly, those particles decompose and produce a rotten, sewage-like smell. Fix: Remove and clean the filter with dish soap and warm water. Do this monthly.

2. Food Trapped in the Door Gasket

The rubber seal around the door has deep folds that trap food, moisture, and mold. This produces a musty or mildew smell. Fix: Scrub the gasket folds with an old toothbrush and white vinegar. Dry thoroughly after cleaning.

3. Standing Water in the Bottom

If water pools at the bottom of the dishwasher after a cycle, it becomes stagnant and smells. This is usually caused by a clogged filter, blocked drain, or kinked drain hose. Fix: Clean the filter and check the drain area for blockages.

4. Grease and Soap Scum Buildup

Over time, grease and soap scum coat the interior walls, spray arms, and heating element. When heated repeatedly, this buildup develops a rancid smell. Fix: Run a vinegar cycle followed by a baking soda cycle.

5. Mold and Mildew

The warm, moist environment inside a dishwasher is ideal for mold growth — especially in the gasket, filter area, and around the door edges. Fix: Clean with white vinegar (which kills mold spores) and leave the door ajar between cycles to allow the interior to dry.

6. Dirty Spray Arms

Food and grease trapped inside the spray arms can decompose and contribute to odors. Fix: Remove and clean the spray arms every 3-6 months.

7. Infrequent Use

If the dishwasher sits unused for extended periods, water in the drain trap can evaporate, allowing sewer gases to enter. Fix: Run a short cycle with just water every week or two if you don't use it regularly.

How to Eliminate Dishwasher Smell: Step-by-Step

Step 1: Clean the filter

Remove and scrub the filter under warm running water with dish soap. This alone fixes the smell in most cases.

Step 2: Scrub the door gasket

Use an old toothbrush and white vinegar to scrub the gasket folds. Wipe dry with a microfiber cloth.

Step 3: Run a vinegar cycle

Place a cup of white vinegar on the bottom rack and run a hot cycle. This dissolves grease, kills bacteria, and neutralizes odors throughout the interior.

Step 4: Run a baking soda cycle

Sprinkle 1 cup of baking soda on the bottom and run a short hot cycle. Baking soda absorbs remaining odors and brightens the interior.

Step 5: Use an Affresh tablet

For persistent odors, drop an Affresh Dishwasher Cleaner tablet into the bottom of the empty dishwasher and run a hot cycle. These tablets are specifically formulated to clean the pump, hoses, and internal components where odor-causing bacteria hide.

Preventing Dishwasher Odors Long-Term

• Clean the filter monthly.
• Leave the door slightly ajar after every cycle to allow the interior to dry.
• Run a vinegar or Affresh cycle monthly.
• Scrape food off dishes before loading.
• Wipe the door gasket every 2-4 weeks.
• Run the dishwasher at least once a week to prevent stagnant water.

Frequently Asked Questions

Why does my dishwasher smell like rotten eggs?

A rotten egg smell is usually caused by sulfur-producing bacteria in decomposing food trapped in the filter or drain. Clean the filter immediately and run a hot vinegar cycle.

Why does my dishwasher smell like fish?

Fish smell usually comes from food residue in the filter or spray arms. Clean both thoroughly and run a vinegar cycle.

Why does my dishwasher smell like burning?

A burning smell can indicate food or plastic has fallen onto the heating element. Check the bottom of the dishwasher for any melted items. If the smell persists with nothing visible, contact a technician.

Why does my new dishwasher smell?

New dishwashers sometimes have a plastic or chemical smell from manufacturing. Run 2-3 empty cycles with a cup of white vinegar to eliminate it.