A dishwasher should smell clean, or at least neutral. If you open the door and get hit with a rotten-egg odor, something is usually trapped in the filter, sitting in the drain, or coming from the plumbing or water supply. The good news: many causes are simple to check. The important exception is a rotten-egg smell that could be natural gas, so start by making sure the odor is coming from the dishwasher and not the room or another appliance.
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First, make sure it isn’t a gas leak
Natural gas is given a strong sulfur-like smell so leaks are easier to notice. If you smell rotten eggs near the dishwasher but can’t tell where it’s coming from, or the odor is strong throughout the kitchen, treat it as a possible gas leak. Don’t turn lights or appliances on or off, and don’t use a phone inside. Leave the building and call your gas utility or emergency services from outside.
If the smell appears only when you open the dishwasher and fades when you close it, food residue or a drain issue is more likely. Still, take a moment to check the area around the stove, water heater, and any gas connections. Safety comes before cleaning.
Why does a dishwasher smell like rotten eggs?
A rotten-egg smell often comes from sulfur compounds produced as bacteria break down food waste. A dishwasher is warm, damp, and full of small spaces where bits of food can collect. That makes it a good place for odor-causing residue to build up, especially if the machine isn’t draining well or sits closed between uses.
Sometimes, though, the odor doesn’t start inside the dishwasher at all. A drain connection, sink plumbing, or smelly hot water can send the odor back into the appliance. The source matters because wiping the interior won’t fix a plumbing or water-supply problem.
Common causes of a rotten-egg smell
1. A dirty filter or food caught in the sump
The filter catches food particles so they don’t circulate through the dishwasher or clog the drain. Over time, grease, rice, seeds, and other scraps can collect there. In a warm, wet environment, the food breaks down and develops a strong odor.
Many filters sit at the bottom of the dishwasher, beneath the lower rack. Check your owner’s manual before removing one, since designs vary. If it’s removable, rinse it under warm water and gently scrub it with a soft brush. Don’t use a sharp tool that could damage the mesh. Also look around the filter opening for scraps, but avoid reaching into areas you can’t see or access safely.
2. Standing water or a slow drain
A little water may remain in some dishwasher models after a cycle, but a pool of dirty water or food-stained water that lingers is a warning sign. A partly blocked filter, kinked drain hose, or clogged sink connection can stop wastewater from leaving properly. The trapped water then becomes a source of odor.
Run a short cycle and listen for the drain portion. If water remains afterward, check the filter and make sure the drain hose isn’t visibly kinked or crushed. If your sink drains slowly too, the blockage may be in the sink drain or the dishwasher’s shared drain connection. A plumber or appliance technician can help if clearing the accessible filter doesn’t solve it.
3. A clogged or dirty garbage disposal
Many dishwashers drain through a hose connected to the garbage disposal. If the disposal holds old food or has a buildup inside, odor can travel along the drain hose and into the dishwasher. This is especially likely if the smell seems stronger near the sink or appears after the dishwasher empties.
Run cold water and operate the disposal according to its instructions, then see whether the sink odor improves. If the disposal is newly installed, there’s another possibility: the dishwasher inlet may still have its factory knockout plug in place. That plug must be removed for the dishwasher to drain through the disposal. Because removing it involves the plumbing connection, contact the installer or a qualified technician if you’re unsure.
4. A drain hose installed incorrectly
The dishwasher drain hose needs to be arranged so wastewater from the sink or disposal doesn’t flow back into the machine. Many installations use a high loop—a section of hose secured high under the countertop—or an air gap, depending on local plumbing rules and the dishwasher instructions.
If the hose is set up incorrectly, dirty water can return to the dishwasher after it drains. That can leave the bottom of the tub smelly even after a wash cycle. Look under the sink for a hose that dips low or appears disconnected, but don’t change the setup unless you know what your model and local plumbing requirements call for. A plumber or installer can confirm the correct arrangement.
5. Food and grease on the door, gasket, or spray arms
The filter isn’t the only place that catches residue. Grease and food can cling to the door edges, the rubber gasket, the bottom corners, and the small holes in the spray arms. These areas may not get a strong rinse, so a thin film can remain and smell unpleasant.
Wipe the gasket and door edges with a damp cloth and mild dish soap. Check the spray-arm holes for visible debris; use a soft brush or follow the manual’s cleaning instructions. A clogged spray arm can also weaken the wash, leaving more food behind on dishes and inside the tub.
6. Sewer gas or a plumbing problem
If the dishwasher looks clean but smells like a drain, the odor may be coming through the plumbing. A dry or poorly functioning sink trap, a blocked vent, or a problem with the dishwasher drain connection can allow sewer-like smells to reach the kitchen. You might notice the odor at the sink as well as inside the dishwasher.
Try to identify whether the smell is strongest at the dishwasher, the sink drain, or both. If it persists after cleaning and the sink also smells, a plumber can inspect the trap, venting, and drain connections. Don’t pour harsh drain chemicals into the dishwasher; they can damage parts and may create hazardous fumes if mixed with other cleaners.
7. Sulfur-smelling water
If the odor appears whenever you use hot water—not just when you open the dishwasher—the water supply may be the source. Some homes, particularly those on well water, have naturally occurring sulfur compounds. In other cases, a water heater can contribute to a sulfur smell.
Compare the water from the hot and cold taps in a few rooms. If the odor comes from hot water at several faucets, the water heater may need attention. If it comes from both hot and cold water, the source may be the incoming water supply. A plumber or water-treatment professional can test the water and recommend a safe fix. Don’t assume the dishwasher needs replacing when the same smell is present at other taps.
How to find the source
A quick comparison can narrow things down before you start taking anything apart:
| What you notice | Possible cause | What to check next |
|---|---|---|
| The smell is strongest inside the dishwasher | Food in the filter, sump, gasket, or spray arms | Clean accessible parts and run a maintenance cycle |
| Dirty water remains after a cycle | Drain blockage, kinked hose, or drain-connection problem | Check the filter and ask for help if water still won’t drain |
| The sink and dishwasher both smell | Garbage disposal or sink plumbing | Check the disposal and contact a plumber if the odor continues |
| Hot water smells at multiple faucets | Water heater or hot-water supply | Have the water heater or water tested |
| The odor is strong throughout the room | Possible gas leak or another household source | Leave and call the gas utility or emergency services from outside |
How to clean a smelly dishwasher
Start with the simple, low-risk steps. Check your dishwasher manual first, especially before removing parts or using a cleaning product. Then try this routine:
- Remove visible food. Take out the bottom rack and look for scraps around the filter and tub floor.
- Clean the filter. Remove and rinse it as directed by the manufacturer. Use a soft brush for stuck-on residue.
- Wipe the door and gasket. Use a damp cloth with mild dish soap, then wipe away soap residue.
- Check the spray arms. Clear visible debris only as directed in the manual.
- Run a dishwasher-cleaning cycle. Use a cleaner labeled for dishwashers and follow its instructions. Don’t combine cleaning products.
Never mix bleach with vinegar, ammonia, or other cleaners. These combinations can release dangerous fumes. Also avoid pouring drain cleaner into the dishwasher. If you use a product, make sure it’s meant for dishwasher interiors and safe for your appliance.
How to keep the odor from coming back
Scrape large food scraps off plates before loading them, but you usually don’t need to pre-rinse every dish unless your dishwasher manual recommends it. Modern machines are designed to wash soiled dishes, and a little food can help the detergent work as intended. What you do want to avoid is letting large scraps collect in the filter.
Clean the filter on the schedule in your manual, or more often if you wash heavily soiled dishes. Leave the door slightly open after a cycle if the manufacturer allows it; airflow helps the interior dry instead of staying warm and damp. If you’re away for a long time, make sure the dishwasher is clean and dry before you leave.
It’s also worth checking the sink and disposal now and then. Since the dishwasher often shares a drain connection with the sink, a fresh-smelling dishwasher can depend on a clean, properly draining sink line.
When to call a professional
Call an appliance technician if the dishwasher repeatedly holds dirty water, won’t drain, or smells bad again soon after a thorough cleaning. Those signs can point to a pump, hose, sensor, or installation problem that needs a closer look.
Call a plumber if the sink and dishwasher both smell, if you suspect sewer gas, or if you see a loose or leaking drain connection. If hot water smells sulfurous at several taps, ask a plumber or water-treatment professional to assess the water heater or supply. And if you suspect natural gas, leave immediately and call from outside rather than troubleshooting indoors.
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Frequently Asked Questions
Is a rotten-egg smell in a dishwasher dangerous?
It’s often caused by food residue or a drain issue, but don’t ignore a strong smell that might be natural gas or sewer gas. If the odor fills the room or you can’t identify its source, leave and contact the appropriate utility or professional from a safe location.
Why does my dishwasher smell worse after a cycle?
A wash cycle can loosen food and move dirty water toward the drain. If the filter is dirty or the machine isn’t draining fully, that residue may become more noticeable when you open the door. Check for standing water and clean the filter.
Can I use vinegar to remove the smell?
Only use a cleaning method approved by your dishwasher’s manufacturer. A dishwasher-safe cleaner is a straightforward option. Never mix vinegar with bleach or other cleaners, and don’t pour cleaning products into the machine unless the instructions say to.
Why does my dishwasher smell when the sink doesn’t?
Food may be trapped in the dishwasher filter, gasket, or sump, or wastewater may be lingering in the tub. Clean the accessible parts and check whether water remains after a cycle. If the odor keeps returning, the drain hose or installation may need inspection.
Conclusion
A rotten-egg smell usually means food residue, standing water, a drain connection, or sulfur-smelling water needs attention. Start by checking the filter and whether the dishwasher drains fully, then compare the odor with what you notice at the sink and other faucets. If the smell is strong across the room or could be natural gas, leave first and get help from a safe location.
