Why Does My Dishwasher Smell Bad?

A dishwasher that smells musty, sour, or like rotting food is one of the most common appliance complaints. The smell comes from bacteria, mold, and food residue building up in areas that don't get fully rinsed during a cycle. Here's where it comes from and how to get rid of it for good.

The Main Culprits

Clogged or Dirty Filter

The filter at the bottom of the dishwasher traps food particles from every cycle. If it's not cleaned regularly, trapped organic matter decomposes --- producing a foul smell that gets blown around the tub and onto your dishes. This is the most common source of dishwasher odor.

Clean the filter every 1--2 months. Remove it, rinse under warm water, scrub with a soft brush, and reinstall. If the smell is severe, soak the filter in white vinegar for 20 minutes before scrubbing.

Door Gasket Mold

The rubber door gasket collects moisture, food splatter, and detergent residue. In the folds and crevices of the gasket, mold and mildew thrive --- producing the classic musty dishwasher smell. Pull back the gasket folds and inspect: black or dark spots are mold.

Clean the gasket with a solution of equal parts white vinegar and water using an old toothbrush to get into the folds. For black mold that won't come off, a small amount of diluted bleach solution works, but rinse thoroughly afterward.

Food Debris in the Spray Arms or Tub

Food debris that bypasses the filter can get trapped in the spray arm jets, behind the filter assembly, or in the tub's corners and low points. Over time this rots and produces odor. Running a cleaning cycle (see below) addresses this.

Standing Water in the Drain Area

A small amount of water at the very bottom of the tub is normal --- it keeps the door seal moist. But larger amounts of standing water indicate a drain issue and are a breeding ground for bacteria. If you consistently see more than a cup of water in the tub after a cycle, address the drain problem first.

How to Deep Clean and Deodorize Your Dishwasher

Step 1: Clean the Filter and Spray Arms

Remove and clean the filter as described above. Clear any clogged jets in the spray arms with a toothpick and rinse.

Step 2: Vinegar Cycle

Place a dishwasher-safe bowl filled with 2 cups of white vinegar on the bottom rack of an empty dishwasher. Run a full hot cycle. The vinegar dissolves mineral deposits, cuts through grease buildup, and kills odor-causing bacteria throughout the entire interior.

Step 3: Baking Soda Cycle

After the vinegar cycle, sprinkle 1 cup of baking soda across the bottom of the empty tub and run a short hot cycle. Baking soda neutralizes any remaining odors and brightens the interior.

Step 4: Clean the Gasket and Edges

After the cleaning cycles, wipe down the door gasket, the door edges, and the interior walls with a damp cloth. Pay special attention to the bottom corners and the area around the filter.

Preventing Odor Going Forward

• Scrape (don't pre-rinse) dishes before loading --- large food particles feed bacteria
• Clean the filter monthly
• Leave the door slightly ajar after each cycle to allow the interior to dry out
• Run a cleaning cycle monthly with vinegar or a commercial dishwasher cleaner
• Wipe the gasket dry after the last cycle of the day