You open the dishwasher expecting clean dishes and get hit with a sour, musty, or downright sewage-like smell instead. It is one of the most common kitchen complaints we hear from Metro Detroit homeowners, and the good news is that most of the time you can fix it yourself in under an hour.
The smell is almost always a sign that something is trapped where it should not be, or that water is not draining the way it should. Below we walk through what causes the odor, how to clean it out step by step, and how to tell when the problem is actually in your plumbing rather than the appliance itself.
What a Smelly Dishwasher Is Telling You
A dishwasher is a warm, damp, closed box. That is a friendly environment for bacteria and mold, and it only takes a little leftover food to feed them. When you notice a bad smell, your dishwasher is usually flagging one of these problems:
- Food particles caught in the filter, spray arms, or door seal
- Grease and soap scum coating the inside of the tub
- Mold or mildew growing in damp corners and around the gasket
- A clogged or dirty drain hose holding dirty water
- A drain or garbage disposal issue letting sewer gas back up into the machine
The type of smell is a useful clue. A musty or moldy smell points to mildew and standing water. A rotten, food-like smell points to trapped scraps. A smell like rotten eggs or sewage points to a drain or venting problem, and that one is worth paying attention to because it often sits on the plumbing side.
The Most Common Reasons a Dishwasher Smells
A dirty filter. Modern dishwashers have a removable filter at the bottom that catches food so it does not recirculate onto your dishes. When that filter is not cleaned regularly, it turns into a small compost pile. This is the number one cause of a smelly dishwasher.
Food stuck in the spray arms and edges. Bits of food lodge in the spray arm holes, along the bottom edge of the door, and inside the rubber gasket. These spots stay wet and rarely get scrubbed.
Grease and soap scum buildup. Over months of use, a film of grease and detergent residue builds up on the tub walls and hidden surfaces. That film holds odor and feeds bacteria.
A clogged or kinked drain hose. If the hose that carries dirty water out of the dishwasher is partially clogged or looped incorrectly, water sits in the line and turns foul. This one crosses over into plumbing territory.
A problem with the garbage disposal or drain. Most dishwashers drain through the garbage disposal or a shared sink drain. If the disposal is dirty or the drain is partly clogged, that smell travels straight back into the dishwasher.
How to Clean a Smelly Dishwasher, Step by Step
You can knock out most dishwasher odors with items you already have at home. Set aside about 30 to 45 minutes and work through these steps in order.
Step 1: Clear out visible food and debris. Pull out the bottom rack and look at the floor of the tub. Remove any chunks of food, broken glass, or gunk you can see. Wipe around the edges and the base of the spray arm.
Step 2: Remove and clean the filter. Twist out the cylindrical filter at the bottom (your owner’s manual shows exactly how). Rinse it under hot running water and scrub it with a soft brush and a drop of dish soap. If it is coated in grime, let it soak in warm soapy water for a few minutes first. Reinstall it when it is clean.
Step 3: Wipe the gasket and door. The rubber seal around the door traps food and moisture. Wipe it down with a damp cloth and a little soapy water, getting into the folds. Do the same for the inside of the door, where splash residue collects.
Step 4: Clean the spray arms. Check the small holes in the spray arms for clogs. A toothpick or a thin piece of wire clears out anything stuck. Blocked holes lower cleaning power and let odor-causing residue linger.
Step 5: Run a vinegar cycle. Place a dishwasher-safe bowl with one cup of white vinegar on the top rack. Run a hot water cycle with the dishwasher empty. Vinegar cuts through grease, soap scum, and mild bacteria buildup.
Step 6: Follow with baking soda. Sprinkle about a cup of baking soda across the bottom of the tub and run a short hot cycle. This deodorizes and lifts any leftover film. Vinegar and baking soda do the same job as pricey commercial cleaners for a fraction of the cost.
Step 7: Check the garbage disposal. Since most dishwashers drain through the disposal, run it with cold water and a little dish soap, or grind a few lemon or citrus peels to freshen it. A dirty disposal will keep sending its smell back into the dishwasher no matter how well you clean the tub.
Quick Reference: Match the Smell to the Cause
| What you smell | Most likely cause | First thing to try |
|---|---|---|
| Musty or mildew | Mold and standing moisture | Vinegar cycle, dry the gasket, leave the door ajar |
| Rotten food | Trapped scraps in filter or spray arms | Clean the filter and spray arm holes |
| Rotten eggs or sewage | Drain, disposal, or venting issue | Clean the disposal, check the drain hose loop |
| Sour, wet-laundry smell | Grease and soap scum buildup | Vinegar plus baking soda cycles |
| Burning or plastic smell | An item melted on the heating element | Stop the cycle, remove the item, inspect the element |
When the Smell Is a Plumbing Problem
Cleaning fixes the large majority of dishwasher odors. But if you have scrubbed the filter, run vinegar and baking soda, and cleaned the disposal and the smell keeps coming back, the cause is probably in your plumbing rather than the appliance. This is where a licensed plumber, not an appliance cleaner, is the right call.
Watch for these signs:
- A sewage or rotten-egg smell that returns fast. That odor is often sewer gas making its way back through the drain line, which can point to a dry or faulty drain trap or a venting problem.
- Water pooling at the bottom of the dishwasher. If the machine will not drain fully, the drain hose or the sink drain it connects to may be clogged.
- Gurgling in the sink when the dishwasher drains. Gurgling usually means air is struggling to move through the line, a classic clog or venting symptom.
- A high drain loop or air gap that was installed wrong. The dishwasher drain hose needs a proper high loop or air gap to keep dirty sink water from flowing back into the machine. When that is missing or installed incorrectly, odor and backflow follow.
These are drain and venting issues, and they are exactly what our team handles every day. Trying to force them with more cleaning will not solve the root cause.
How Hard Water in Metro Detroit Makes It Worse
Much of the Metro Detroit area runs on moderately hard water. Over time, the minerals in hard water leave scale and film on the inside of your dishwasher, on the spray arms, and along the drain path. That buildup gives food particles and bacteria more to cling to, which means odors come back faster here than they might in a soft-water home.
If you are cleaning your dishwasher every couple of weeks and still fighting buildup, hard water is likely part of the story. A rinse aid helps, and running a vinegar cycle a little more often keeps scale from taking hold. For homes with heavy scale on faucets and fixtures throughout the house, it may be worth a conversation about water treatment.
How to Keep Your Dishwasher Smelling Fresh
A few simple habits keep the odor from coming back:
- Scrape plates before loading. You do not need to pre-rinse everything, but knock the large scraps into the trash so they do not sit in the filter.
- Clean the filter monthly. A two-minute rinse once a month prevents the biggest cause of odor.
- Run a vinegar cycle every few weeks. This keeps grease, film, and mild mold from building up.
- Leave the door open after a cycle. Letting the tub air out and dry prevents the damp, musty smell that mold loves.
- Use a rinse aid. It helps dishes dry and cuts down on the film that hard water leaves behind.
- Run the dishwasher regularly. A machine that sits unused for days holds standing water that turns stale. If you travel, run an empty hot cycle when you get back.
When to Call WaterWork Plumbing
If the smell keeps returning after a thorough cleaning, or you notice slow draining, gurgling, or standing water, the problem is in your drain line and it is time to bring in a professional. Our licensed plumbers serve homeowners across Metro Detroit, including Birmingham, Royal Oak, Troy, Grosse Pointe, Beverly Hills, and the surrounding communities. We will find where the odor is really coming from, clear any clog, check the drain connection and air gap, and make sure your dishwasher drains clean.
Call us at 248.542.8022 or schedule online, and we will get your kitchen back to smelling the way it should.
Frequently Asked Questions
Why does my dishwasher smell even after I clean it?
If the smell comes back quickly after cleaning, the cause is usually deeper than the tub. Check the garbage disposal, the drain hose, and how the hose loops under the sink. A returning sewage smell points to a drain or venting issue that a plumber should inspect.
Why does my dishwasher smell like sewage or rotten eggs?
That smell is often sewer gas backing up through the drain line, or dirty sink water flowing back into the machine because the drain hose lacks a proper high loop or air gap. This is a plumbing problem rather than a cleaning problem, and it is worth having checked.
Can I use bleach to clean a smelly dishwasher?
Bleach can help with mold in some dishwashers, but it can damage machines with stainless steel interiors or parts. Vinegar and baking soda are safer for most units and handle everyday odor well. Check your owner’s manual before using bleach.
How often should I clean my dishwasher?
Rinse the filter about once a month and run a vinegar cycle every two to three weeks. In hard-water areas like Metro Detroit, sticking to that schedule keeps mineral scale and odor from building up.
Is a smelly dishwasher a sign of a bigger plumbing issue?
Sometimes. If cleaning does not solve it, or you also notice slow draining, gurgling, or standing water, the dishwasher may be tied into a clogged or poorly vented drain. A plumber can confirm the cause and fix it.
