A persistent, unpleasant odor emanating from a dishwasher signals that food particles and grease are accumulating in areas the normal wash cycle cannot reach. This buildup reduces the appliance’s cleaning effectiveness over time. Addressing this issue requires a two-pronged approach: a physical deep clean to remove the primary source of the grime, followed by deodorizing cycles and preventative habits to maintain freshness.
Physical Deep Cleaning: Targeting the Source
The most common source of dishwasher odor is the filter, which is designed to trap large food debris and prevent it from recirculating or clogging the drain pump. To clean it, first remove the bottom dish rack to access the filter, which is typically located at the base of the tub, often near the bottom spray arm. Most filters consist of a cylindrical upper assembly and a flat lower screen; gently twist the upper part counterclockwise to unlock and lift it out. Rinse both parts under warm running water to remove loose soils and use a soft brush or old toothbrush with mild dish soap to scrub away stubborn, stuck-on residue or calcium deposits.
Another area prone to accumulating grime is the spray arms, which can become clogged with small food particles, reducing the force and coverage of the water jets. Carefully remove the lower spray arm, and any upper arms, by unscrewing or unlatching them according to your model’s instructions. Use a toothpick or a thin wire to clear the small holes of any debris, ensuring the water can flow freely. After clearing the holes, rinse the arms thoroughly before reattaching them, making sure they spin freely.
Finally, the rubber gasket or seal around the door is a prime location for mold and mildew growth due to trapped moisture and food splatter. This area requires manual attention, as the high-pressure water jets do not effectively clean it. Wipe down the entire seal with a cloth dampened with warm, soapy water, paying close attention to the folds and crevices where black grime often accumulates.
Quick Deodorizing Cycle Solutions
Once the physical debris is removed, running a cleaning cycle with household agents can help dissolve grease and neutralize lingering smells. White vinegar is highly effective because its acetic acid content helps break down mineral deposits and soap scum that cling to the interior walls and plumbing. Place one cup of white vinegar in a dishwasher-safe cup or bowl on the top rack and run a full, empty hot water cycle. Placing the vinegar in a cup prevents it from immediately washing away and allows it to be dispersed throughout the cycle. Note that prolonged, direct contact with undiluted vinegar can potentially degrade rubber seals over time.
Following the vinegar cycle, a separate cycle using baking soda can further deodorize the machine. Sprinkle about a half-cup of baking soda across the bottom of the empty dishwasher tub. Baking soda is a natural odor absorber that helps neutralize acidic residue and eliminates remaining foul smells. Run a short, hot rinse cycle to distribute the baking soda and flush it through the system. For heavy buildup that resists home remedies, commercial dishwasher cleaning tablets are available, which are specifically formulated to target limescale and grease in the machine’s internal components.
Preventative Habits for a Fresh Dishwasher
Maintaining a fresh dishwasher requires adopting simple habits that minimize the amount of food and moisture left inside the appliance. Before loading dishes, scrape large food particles, such as bones or excessive sauces, directly into the trash to prevent them from clogging the filter and spray arms. While pre-rinsing is not necessary for modern detergents, removing bulk debris significantly reduces the organic matter available to decompose and cause odors.
Running the dishwasher regularly prevents food residue from sitting and decomposing inside the machine for extended periods, which is a primary cause of mildew and sour smells. If the machine is not run daily, consider running a quick rinse cycle to flush out any residue until a full load is ready. Additionally, before starting a cycle, run the kitchen sink’s hot water tap for a minute to ensure the water entering the dishwasher is already hot. Starting with hot water immediately improves the detergent’s effectiveness and helps dissolve grease from the beginning of the wash.