At a glance
Symptoms
- • Musty, moldy, or swampy smell when opening the door
- • Sewage-like odor emanating from the tub between cycles
- • Dishes smell like 'wet dog' or raw eggs after washing
- • Visible black or pink slime on the door gasket and hinges
- • Standing water in the bottom of the tub that smells stagnant
- • Foul smell specifically during the drying cycle
Common causes
- • Clogged or dirty bottom filter assembly trapping rotting food
- • Food particles (like seeds or rice) trapped inside the spray arms
- • Biofilm and hard water scale buildup on the tub walls
- • Dirty, moldy, or deteriorating rubber door gasket
- • Clogged sink air gap or lack of a high loop in the drain hose
- • Kinked or partially clogged drain hose holding stagnant water
Safety First — Read Before You Start
- •Always unplug the dishwasher or flip the circuit breaker before reaching deep into the drain or motor area.
- •Never mix bleach with vinegar or ammonia-based cleaners; this chemical reaction creates highly toxic chloramine or chlorine gas.
- •Wear heavy-duty rubber gloves when cleaning the filter pit—broken glass, sharp bone fragments, and pop-tabs frequently hide in the sump.
- •If you smell a burning plastic, fishy electrical, or ozone odor, stop immediately. Turn off the breaker and call a professional, as this indicates melting wires or a failing control board.
Tools & supplies you'll need
- White vinegar (2 cups)
- Baking soda (1 cup)
- Old toothbrush or soft nylon scrubbing brush
- Sponge and mild dish soap
- Toothpicks, tweezers, or a piece of stiff wire
- Torx or Phillips screwdrivers (for removing some spray arms)
- Shop-vac or turkey baster (for clearing standing water)
Step-by-step instructions
Diagnose the Odor and Clear Standing Water
Before taking anything apart, you need to identify what kind of smell you're dealing with. A sewage smell usually indicates a plumbing issue (like a clogged drain hose or air gap backflow), while a musty or 'wet dog' smell points to mold, biofilm, or rotting food inside the tub. Start by completely emptying the dishwasher. Pull out the bottom rack and inspect the sump area (the recessed pit under the lower spray arm). If there is standing water that rises above the filter screen, your odor is likely caused by a drainage failure. Use a sponge, turkey baster, or wet/dry Shop-Vac to remove this stagnant water. If the water returns when you run your kitchen sink, you have a plumbing crossover issue, likely at the garbage disposal or air gap.
Tip: In Southern California hillside homes, older plumbing can sometimes cause slow sink drains, which backs up into the dishwasher if the air gap is bypassed.
âš Warning: Do not stick your bare hands into opaque, murky standing water. Always use gloves and a sponge to avoid unseen sharp objects.
Remove and Scrub the Filter Assembly
The vast majority of modern dishwashers do not have built-in hard food disposers (macerators) because they are too loud. Instead, they use a manual filter system to catch debris. Over time, grease, food bits, and hard water scale (especially common with the 250-400 ppm hard water in Los Angeles and Orange County) turn this filter into a smelly, rotting mess. Twist the main cylindrical filter counterclockwise and lift it out. Then, remove the flat mesh screen beneath it. Take both pieces to the sink and scrub them thoroughly with dish soap, warm water, and an old toothbrush. Pay special attention to the fine mesh, which can get clogged with a clear, greasy biofilm that traps odors. Rinse until water flows freely through the mesh.
Tip: Make this a habit! Cleaning your dishwasher filter once a month is the single most effective way to prevent odors and ensure your dishes actually get clean.
Clean the Door Gasket and Tub Edges
The rubber seal that lines the perimeter of the dishwasher door (the gasket) is a prime breeding ground for mold and mildew, particularly in humid coastal areas like San Diego, Ventura, or Santa Monica. Because water doesn't directly spray the very edges of the door during a cycle, food splatters and dirty water can collect there and fester. Dip an old toothbrush or a sponge into a mixture of warm water and a few drops of dish soap (or a 50/50 vinegar and water solution). Gently pull back the folds of the rubber gasket and scrub away any black mold, pink slime, or hidden grime. Wipe down the bottom edge of the door, the hinges, and the detergent dispenser area, as these spots are notorious for holding foul-smelling residue.
âš Warning: Do not use bleach on the rubber door gasket. Bleach can dry out the rubber, causing it to crack, warp, and eventually leak water onto your kitchen floor.
Inspect and Clear the Spray Arms
If your filter is clean but the dishwasher still smells like rotting food, check the upper and lower spray arms. Small food particles like rice grains, citrus seeds, or bits of eggshell can get forced into the tiny water jets, where they sit and rot. Most lower spray arms can be removed simply by pulling them straight up or unscrewing a plastic locking nut. Upper spray arms usually unscrew from the center hub. Take the arms to the sink and inspect the holes. If you see debris stuck inside, use a toothpick, a pair of tweezers, or a piece of stiff wire to pick it out. Run water through the center opening to flush out any loose particles. Reattach the arms and spin them manually to ensure they move freely.
Tip: Avoid using metal needles or safety pins if possible, as aggressively scraping the plastic jets can deform the holes and alter the spray pattern of the water.
Check the Air Gap and Drain Hose High Loop
California plumbing codes heavily feature the use of sink air gaps—that little chrome cylinder sitting next to your kitchen faucet. The air gap prevents dirty sink water from siphoning back into your dishwasher. If the air gap gets clogged with gunk, the dishwasher will hold stagnant, sewage-smelling water. Pull the chrome cover off the air gap, unclip the plastic inner cap, and use a bottle brush or a toothpick to clear out the debris. If you don't have an air gap, check your drain hose under the sink. It must be secured in a 'high loop'—meaning the hose is strapped to the underside of the cabinet, higher than the sink drain inlet. If the hose just lays flat on the cabinet floor, dirty sink water is constantly flowing back into your dishwasher's sump.
âš Warning: Never bypass an air gap or high loop. Without them, hazardous wastewater from your sink or garbage disposal can cross-contaminate your supposedly clean dishes.
Run a Deep-Clean Vinegar and Baking Soda Cycle
Once you have physically removed the source of the odor (food, mold, and clogs), it's time to chemically neutralize the lingering smells and dissolve the hard water scale. Place a dishwasher-safe bowl containing two cups of plain white vinegar on the top rack of the empty dishwasher. Close the door and run a normal cycle on the hottest water setting available (use the 'Sanitize' or 'Heavy' wash option). The vinegar will break down greasy biofilm and mineral deposits. Once that cycle finishes, open the door and sprinkle one cup of baking soda across the bottom of the dishwasher tub. Run a second, short cycle (like a 'Quick Wash') on hot. The baking soda will absorb any remaining odors and gently scour the tub, leaving the interior smelling fresh and looking bright.
Brand-specific notes
Some brands have known design quirks worth knowing about before you start.
Bosch
Bosch dishwashers are incredibly quiet because they lack a hard food disposer, relying entirely on a manual three-part filter system. If your Bosch smells, the filter is almost certainly the culprit. Replacement micro-filters run about $30-$50. Also, Bosch drain hoses often require a very strict high loop under the sink to prevent backflow.
Whirlpool / KitchenAid
Many Whirlpool and KitchenAid models use a 'chopper' assembly near the drain pump. If a piece of glass or bone jams the chopper, food will bypass it and clog the drain line, leading to a swampy smell. If you hear a grinding noise accompanied by the smell, the chopper assembly (a $20-$40 part) or the drain pump ($50-$90) may need replacement.
Samsung
Samsung models featuring the 'WaterWall' or linear wash systems have tracks at the bottom of the tub. These tracks can accumulate a surprising amount of gunk and biofilm. Use a toothbrush to scrub the linear track thoroughly. Additionally, check the rubber flap (check valve) on the drain hose, as they can stick open and allow sink water back in.
LG
LG's Inverter Direct Drive dishwashers are highly efficient but can be sensitive to drain hose routing. If the hose isn't elevated properly, the unit will constantly smell like your garbage disposal. LG also uses a fine-mesh cylindrical filter that requires frequent cleaning, especially if you use gel detergents instead of pods or powder.
GE
GE Profile and Cafe models often feature specialized 'Bottle Wash' jets on the upper rack. Because these jets shoot water directly upward, they can sometimes trap small food particles in their clips. Check these jets if the upper rack smells musty. GE door gaskets are also prone to collecting heavy mold at the very bottom corners where the door meets the tub.
What our techs see most often
In Los Angeles and Orange County, our notoriously hard water combines with modern enzyme detergents to create a stubborn, smelly biofilm. I'd say 80% of our 'smelly dishwasher' calls are solved by just cleaning the filter and clearing the sink air gap. Save yourself the $150 service call and check those two things first!
When to call a professional
- → The sewage or musty smell persists even after deep cleaning the filter, clearing the air gap, and running vinegar/baking soda cycles.
- → The dishwasher is not draining water at all, and clearing the filter/hose doesn't fix it (indicates a failed drain pump or control board).
- → You smell a burning plastic, ozone, or fishy electrical odor. Turn off the breaker immediately; this is a fire hazard.
- → You suspect a dead rodent or pest is trapped behind the kickplate, under the tub, or in the insulation blanket.
- → The unit is leaking water onto the floor from the motor area underneath, causing a stagnant smell under your cabinets.
Dishwasher Maintenance & Replacement Tasks
Step-by-step guides for individual maintenance jobs related to this appliance.
How to Clean a Dishwasher Filter (All Brands)
How to Clean Dishwasher Spray Arms (Unclog the Jets)
How to Descale a Dishwasher with Vinegar or Citric Acid
How to Replace a Dishwasher Door Gasket
Frequently asked questions
Why does my dishwasher smell like a wet dog?
A 'wet dog' smell is typically caused by a combination of bacteria and egg residue. Eggs contain sulfur compounds that bind to the metal and plastic inside the dishwasher. When mixed with the bacteria in a dirty filter and the damp environment, it produces that distinct wet dog odor. Pre-rinsing egg yolk off plates and cleaning the filter will solve this.
How much does it cost to have a professional fix a smelly dishwasher?
If the issue is just a deep cleaning and clearing a clogged air gap or drain hose, a standard service call will run $125 to $180. If the odor is caused by stagnant water due to a failed drain pump, expect to pay $200 to $350 total for parts and labor, depending on the brand.
Can I use bleach to clean the inside of my dishwasher?
Only if your dishwasher has a plastic tub and you are absolutely sure there is no vinegar, ammonia, or rust-removing chemicals inside. Never use bleach in a dishwasher with a stainless steel interior, as it will pit and permanently damage the metal. Stick to vinegar and baking soda for a safer, non-corrosive clean.
Is it normal for a little bit of water to be left in the bottom?
Yes, it is perfectly normal to have a small pool of clean water (about a cup) sitting beneath the filter assembly in the sump pit. This water keeps the rubber seals lubricated and prevents them from drying out and cracking. However, if the water covers the top of the filter or smells foul, that indicates a drainage problem.
Do dishwasher cleaning tablets actually work?
Yes, commercial dishwasher cleaners (like Affresh or Finish) are highly effective. They use citric acid and sodium percarbonate to break down hard water scale and kill odor-causing bacteria. Using one tablet a month is a great preventative measure, costing about $5-$10 for a multi-pack, though they won't fix a physically clogged filter.
Related Repair Guides
Dishwasher Not Cleaning Dishes Properly: Fix Guide
Dishes that come out gritty, filmy, or still flecked with food are usually not a detergent problem — they are a water problem. Hard water mineral deposits, clogged spray arm jets, and a starved water inlet valve cause roughly 80% of these complaints, especially in Southern California where calcium and magnesium levels run high. Most fixes take 30-90 minutes with no special parts.
Dishwasher Not Draining: How to Fix Standing Water
A pool of dirty water sitting at the bottom of your dishwasher after a cycle is one of the most common service calls we get. The good news: roughly 7 out of 10 cases trace back to a clogged garbage disposal connection or a blocked filter — both of which you can fix in under an hour without any special tools.
How to Clean a Dishwasher Filter (All Brands)
A clogged filter is the number one cause of gritty dishes and foul odors. Learn how to locate, remove, and properly scrub your dishwasher's filter assembly to restore peak cleaning performance and protect your drain pump.