There are two completely different dishwasher smells and telling them apart saves an afternoon. A sour, rotting food smell that is strongest when you open the door is organic material sitting inside the machine — in the filter, the sump, the spray arm ends and the gasket folds. A sewer or drain smell, often strongest in the kitchen generally rather than in the machine, is coming up the drain path from the household plumbing and no amount of cleaning the tub will touch it. Work out which you have before you start.
Read this first
- Never mix bleach with vinegar, citric acid or any other cleaner. Chlorine gas is produced in exactly this kind of enclosed space.
- Do not use bleach in a dishwasher with a stainless steel tub or stainless interior parts unless the manufacturer specifically permits it.
- Switch off the breaker before removing the sump cover or reaching into the drain path.
- Broken glass hides in the sump and the filter well. Feel with gloves on, or better, look first with a flashlight.
Step by step
Decide which smell you are dealing with
Open the door on a machine that has been shut for a few hours and smell it directly, then smell the sink drain and the cabinet under the sink. Sour, fermented, food-like means the source is inside the machine. A sewage or stagnant-drain smell that is also noticeable at the sink means the drain path is the problem. If the smell is chemical or burning, stop — that is not a hygiene issue, and a hot electrical smell means switching the breaker off and having it looked at.
Pull and wash the filter
Almost every machine built in the last fifteen years has a removable filter assembly in the floor of the tub — usually a cylindrical coarse filter that twists out and a flat fine screen beneath it. On a machine where nobody has ever removed it, what comes out will explain the smell entirely. Wash both parts in hot soapy water with a toothbrush, rinse thoroughly, and refit them properly, because a filter that is not locked home lets debris into the pump. Make this a monthly habit.
Clean the sump and the area under the filter
With the filter out, look into the sump well with a flashlight. There is a small amount of standing water there by design — that is not a fault, it is what keeps the pump seal wet — but there should not be a layer of sludge, food debris or broken glass. Sponge it out, wipe around the check valve and the drain port, and clear anything caught in the chopper area. Wear gloves and look before you reach; glass chips end up here more often than anything else.
Clear the spray arm jets and the arm ends
Take both spray arms off — most twist or unclip — and rinse them through under a tap. Food particles lodge in the jets, and the sealed ends of the arms collect a slurry that sits wet between cycles and ferments. Poke each jet clear with a toothpick from the outside. Check the upper feed tube at the same time. This step also improves cleaning, so it is worth doing regardless of whether it turns out to be the smell.
Clean the door gasket and the door edges
Run a gloved finger along the underside of the door, the bottom lip below the gasket, and the channel the gasket sits in. That area sits outside the wash zone on most machines, never gets rinsed, and grows a film of grease and food residue. Wipe it all out with hot soapy water and a toothbrush along the seam. Check the gasket itself for splits while you are there, since a torn seal is also a leak waiting to happen.
Check the drain hose has a high loop
This is the fix for a drain smell. The drain hose must rise to a high point — secured up under the countertop or through an air gap on the sink deck — before it drops to the disposal or the waste tee. Without that loop, waste water from the sink can drain back toward the machine and sit in the hose, and sewer gas has a straight path in. Open the sink cabinet and look. Fitting or refitting a high loop is a cable tie and ten minutes.
Check the air gap and the disposal connection
If your installation has an air gap — the small chrome cylinder on the sink deck — pull its cover and clean inside it, because it clogs with debris and then smells and overflows. If the machine drains into a garbage disposal, run the disposal with cold water for a minute; a disposal that has not been cleaned smells, and because the dishwasher drains through it, that smell arrives alongside the dishwasher's own drain water and gets blamed on the machine. Check too that a recently fitted disposal had its knockout plug removed.
Run a hot cleaning cycle and change the habits
With everything physically clean, run the hottest cycle the machine offers, empty, with a proprietary dishwasher cleaner or a cup of citric acid solution. Then change what caused it: scrape plates rather than pre-rinsing them, run the machine often enough that food does not sit in a warm tub for days, and leave the door ajar after a cycle so the tub dries. A machine used twice a week and shut tight between loads will smell again whatever you clean.
What this repair costs
Doing it yourself
$8–$95
Hiring a technician
$80–$300
Prices are general estimates for typical US jobs, not quotes. What you actually pay depends on your appliance's brand and age, the part required, your region, and each shop's labour rate. The DIY figure assumes you supply the labour and buy the part yourself.
Parts you may end up buying
| Part | Install | Typical price | Typical lifespan |
|---|---|---|---|
| Spray Arm | easy | $15–$40 | 5–8 years |
| Inlet Valve | moderate | $15–$40 | 8–12 years |
| Drain Pump | moderate | $35–$120 | 8–12 years |
| Door Latch and Switch Assembly | easy | $20–$80 | 6–12 years |
| Heating Element | moderate | $25–$85 | 8–14 years |
| Float Switch | easy | $10–$35 | 10+ years |
| Door Gasket | easy | $20–$75 | 6–12 years |
| Rack Roller and Adjuster Kit | easy | $12–$50 | 5–10 years |
| Detergent Dispenser | moderate | $30–$100 | 8–12 years |
| Circulation Pump and Motor | advanced | $90–$330 | 8–14 years |
Still not fixed
When to call a pro
Call a plumber, not an appliance technician, if the drain smell persists with a correct high loop and a clean air gap — that points at the household waste line, a dry or missing trap, or a venting problem, and none of those is a dishwasher fault. Call an appliance technician if the smell survives a full clean and a hot cycle, since a machine that is not draining completely at the end of every cycle leaves water somewhere it should not be, and that is worth diagnosing before it turns into a pump repair.
More dishwasher guides
- Dishwasher Not Cleaning — Find Out What It Is Short Of30–60 minutes
- Dishwasher Not Draining — Clear the Standing Water20–60 minutes
- Dishwasher Leaking — Find the Source Before It Damages the Floor30–90 minutes
- Dishwasher Not Drying Dishes — Why, and What Actually Helps15–45 minutes
- Dishwasher Soap Dispenser Not Opening — Why the Pod Is Still There20–60 minutes
- Dishwasher Spray Arm Not Spinning — Restore the Wash Action20–45 minutes
- Dishwasher Door Won't Latch or Stay Closed30–90 minutes
- Dishwasher Won't Start — Work Through the Lockouts First30–75 minutes
- Dishwasher Not Filling With Water — Trace the Supply45–90 minutes
- White Film on Dishes — Hard Water Scale or Permanent Etching?30 minutes plus a test cycle
- Dishwasher Making Noise — Match the Sound to the Part30–75 minutes