Dishwasher Smells Bad: Causes and How to Fix It

A bad smell from a dishwasher almost always comes from trapped food and grease, most often in the filter at the bottom of the tub, or from dirty water that sits in the unit between loads. Cleaning the filter, running an empty hot cleaning cycle and making sure the dishwasher drains fully fixes most odors. A sewage smell that keeps coming back usually points to the drain hose setup or a partial clog.

Match the smell to the cause

Safety first

Unplug the dishwasher or switch off its breaker before reaching into the sump or removing the filter, and let a hot unit cool. If you need to look at the drain hose behind the kick panel, also shut the water supply valve, usually under the kitchen sink on the line to the dishwasher. A burning or electrical smell is different from a food smell: turn off the breaker and do not run the dishwasher again until a technician has looked at it.

Clean it step by step

1. Clean the filter

This is where most odors start. Bosch blames food particles trapped in the filter. Amana and GE both say to pull and scrub the filter first. Most filters twist out from the floor of the tub. Rinse them under running water with mild soap and a soft brush, as Bosch recommends, and wipe out the sump area underneath. Some Amana models have a maintenance-free filter with a foreign object cup instead, which just needs to be emptied when it fills.

How often depends on the brand and how heavily you use it. Bosch suggests about every two months, Frigidaire every two to three months and Beko at least once a week. If you rarely scrape plates, clean it more often.

2. Clean the spray arms, door gasket and dispenser

Samsung says to clean the filter, drain area, spray nozzles and door seal. Clear blocked spray arm holes with a toothpick, as Bosch suggests. Wipe the rubber gasket around the door and the bottom edge of the door, where food collects out of sight. KitchenAid says to wipe the interior and clean out caked detergent from the dispenser.

3. Run an empty cleaning cycle

Run a dishwasher cleaner through an empty hot cycle. Amana suggests doing this about once a month to control odors, and Bosch recommends a cleaner and a descaler a few times a year on the hottest, longest cycle. Frigidaire suggests an empty Heavy or PowerPlus cycle with Sanitize, or an empty cycle with a cup of white vinegar in the tub, about every three months. Samsung says never mix vinegar with detergent and not to use bleach in a stainless tub.

4. Check the water temperature

Grease does not wash away well in lukewarm water. Samsung says water should reach the dishwasher at 120 to 149 degrees F. Run hot water at the kitchen sink before starting a cycle so the first fill is hot.

If the smell keeps coming back

Standing water

Frigidaire says to confirm water is not standing in the tub after a cycle, and Electrolux says to make sure the dishwasher drains properly. Water left in the bottom will go stale. If you see more than a little water after the cycle ends, work through our guide on a dishwasher not draining.

Drain hose high loop or air gap

GE says to confirm the drain hose has a high loop or an air gap so sink water cannot siphon back into the dishwasher. GE's installation instructions call for the loop to rise at least 32 inches, or an air gap where local code requires one or where the drain connection is less than 18 inches above the floor. Without it, dirty water from the sink or garbage disposer can flow back into the tub and cause a sewer smell. Also run the disposer before starting the dishwasher; Amana says to make sure the drain and disposer are clear.

Loads that sit

Electrolux suggests a rinse-only cycle if dishes will sit in the dishwasher for a while before you run it. ENERGY STAR also recommends using the rinse-hold setting rather than pre-rinsing in the sink, which saves water while keeping food from drying on.

Leave the door cracked

A closed, damp tub breeds mildew. Leaving the door slightly open after unloading lets it air out. Some newer models handle this for you; GE says its UltraFresh System empties the sump after the cycle and uses a fan to pull fresh air through the tub.

When it is a repair, not a cleaning

Cleaning will not fix a mechanical cause. Call a technician if water stands in the tub after every cycle even with a clean filter, if the drain hose is damaged or the sump stays dirty, or if there is any burning or electrical smell. A technician will check the drain pump, the drain hose and its connection under the sink, the check valve that keeps water from flowing back, and the heating element. Our dishwasher repair directory lists local companies, and you can search by brand on the Whirlpool, Electrolux and Kenmore pages (Kenmore appliances were sold through Sears). Local pages cover cities such as New York and Miami.

A smell paired with dirty dishes often has the same root cause. See dishwasher not cleaning dishes for more on filters and spray arms.

What it costs

Many odor problems cost nothing beyond a cleaner. If a part is to blame, Fixr lists drain pump replacement at about $150 to $400 and a spray arm replacement at about $75 to $150. Fixr also puts a diagnostic fee at about $50 to $75 per visit. See the dishwasher repair cost guide for more.