Why Does My Dishwasher Smell Like Rotten Eggs – How To Fix It?

Imagine this: you open your dishwasher following its cycle, expecting to smell the fresh scent of clean dishes. Instead, the odor of rotten eggs greets your nose. Disturbing. 

This unpleasant smell could be an indicator of underlying issues with your appliance. In this guide, I’ll help you identify some possible reasons for this unwanted odor and provide quick-fix solutions to restore your dishwasher’s fresh scent. 

By simply following the advice outlined below, you’ll soon be able to locate and correct the problem, leaving your dishes – and your kitchen – with a much better smell. 

Why Your Dishwasher Smells Like Eggs

Anytime your dishwasher starts to emit the sulfuric smell of rotten eggs, the cause is likely due to unnoticed problems. 

Even though the purpose of a dishwasher is to clean and sanitize, it can still become a breeding ground for unpleasant smells. Let’s look at some of the most common causes of this occurrence. 

Rotten Food Particles

One major factor leading to unwanted aromas from your dishwasher is leftover food particles trapped inside the appliance. Just as when food left outside of your fridge can turn nasty, food left inside your dishwasher can also rot and give off an unpleasant smell. 

Why do these food particles create such a disagreeable odor? To answer this question, let’s look at the science involved. 

Decomposition of Organic Matter: 

The truth is, no matter how thoroughly you rinse your dishes before loading your washer, not all food particles will be removed. As a result, these undetected particles begin to collect at the bottom, in the corners, or even in the dishwasher’s filter. 

Over time, these trapped food particles undergo a natural decomposition in which anaerobic bacteria (bacteria that thrive without oxygen) begin to break down the organic components of the leftover food. 

Hydrogen Sulphide Production: 

Perhaps the most unpleasant aspect of this microbial decomposition and the presence of anaerobic bacteria is the creation of hydrogen sulfide gas. That’s the scientific name for what you and I might call the smell of rotten eggs. 

As you will have found out, when it comes to this natural gas, a little can be a lot. Even the slightest traces of hydrogen sulfide gas can result in a pungent and displeasing odor that fills the entire kitchen. 

Stagnant Environment:

Compared to a trash bin, where food particles decay in the open, the inside of a dishwasher is a humid and closed-off setting. 

The limited airflow inside creates a stagnant environment where anaerobic bacteria can thrive, resulting in higher levels of hydrogen sulfide gas. When a dishwasher remains closed after a cycle, the warmth and humidity can speed up this troublesome process. 

Infrequent Cleaning:

The longer these overlooked food particles remain trapped in your dishwasher, the more unpleasant the decomposition process becomes. 

If you’re not cleaning your dishwasher frequently or adequately, you’ll soon find that these unwanted bits of food will have more time to decompose and release their poisonous gases. 

If your dishwasher is allowed to get dirty, a sticky layer of grease and grime can form, causing even more food particles to get trapped and the decomposition process to worsen. 

Interaction with Dishwasher Components: 

All this would be bad enough if the food particles remained loose in the appliance. Unfortunately, they don’t. 

Food particles can mix with detergent residues, hard water mineral deposits, or even the plastic and rubber components inside the dishwasher. These interactions can intensify and worsen the already unpleasant smell. 

As you can see, the reason for the occasional rotten egg smell coming from your dishwasher is a combination of natural decomposition and the design features of the appliance. 

To restore your dishwasher’s primary purpose of delivering clean, fresh-smelling dishes, it’s essential to address the issue of trapped and rotting food particles. 

  1. Pooling or Leaking Wastewater

Another leading culprit behind that undesirable rotten egg smell could be pooling or leaking wastewater. 

To illustrate this phenomenon, I’ll briefly outline the properties of wastewater, its conditions inside the dishwasher, and the chemical processes involved when water doesn’t drain as it should. 

Nature of Wastewater: 

Firstly, it’s important to note that wastewater generated from a dishwashing cycle isn’t just water. It’s a sludgy cocktail of leftover food particles, detergent residues, grease, and even microbes. 

When all these components come together in a pool of wastewater, they can not only cause your dishwasher to gurgle when draining but also cause the leftover sludge to undergo various unpleasant chemical and biological reactions. 

Just as you’ve seen above when it comes to food particles, the components of undrained wastewater can interact and decay, leading to some very unwelcome results. 

Production of Hydrogen Sulphide:

Like within trapped food particles, anaerobic bacteria can also thrive in other oxygen-deprived settings, such as pooling wastewater. Again, this results in a breakdown of organic matter and the displeasing occurrence of hydrogen sulfide gas (H2S), notorious for its distinctive rotten egg smell. 

This gas is highly potent. Even in its minor concentrations, H2S can fill an entire kitchen with its characteristic stench. 

Stagnancy and Warmth: 

As I’ve already noted, the sealed-off environment of a dishwasher, especially when there’s pooling wastewater inside, can be extremely warm and humid following a washing cycle. These conditions make it an ideal setting for microbial activity. 

Because the stagnant nature of pooled wastewater reduces oxygen content, a perfect habitat is established for anaerobic bacteria to multiply and produce foul-smelling gases like hydrogen sulfide. 

Compound Problems: 

It’s not just the presence of anaerobic bacteria that’s a concern when it comes to pooled wastewater, but also the accumulation of other odor-causing substances. Fats and grease, for example, can turn rancid, while detergent residues can interact unpleasantly with trapped food particles. 

If left to stagnate, pooled wastewater can produce a pungent hybrid of various unwelcome smells. 

Ineffective Sealing: 

It may be possible that your dishwasher has a malfunctioning seal or other mechanical issue, causing wastewater to spill over into areas not usually exposed to water. 

Any water ending up in hard-to-reach spots can be challenging to locate and dry, resulting in anaerobic bacterial colonies and further odor problems. 

Interaction with Dishwasher Materials:

Pooling wastewater, whether it’s acidic or alkaline, can also react with the structural materials of the dishwasher itself, such as metal, plastic, or rubber components. These interactions can produce unique and equally disagreeable smells or even intensify the smell of rotten eggs. 

As you can see, due to the toxic mixture of organic substances and stagnant conditions, the presence of pooling or leaking wastewater can be a prime cause for the presence of unwanted smells emanating from your dishwasher. 

Addressing this issue can prove vital in eliminating foul odors and ensuring your dishwasher operates effectively and hygienically. 

6 Ways to Fix a Smelly Dishwasher

There’s no need to worry. Removing unpleasant smells from your dishwasher is easier than it might seem. I’ve included a comprehensive list of tasks below you can undertake to eliminate those unwanted odors and keep your dishwasher in good working order. For a helpful visual aid, you might also want to refer to this video:


1. Wipe the Door Gasket

First, open the dishwasher door and, using a damp cloth, clean the rubber gasket, ensuring that you reach every crevice. Wiping away food particles and grime will work wonders in preventing odor buildup. 

2. Clean the Drain Filter

Next, remove the bottom rack to gain access to the drain filter. Carefully turn and lift the filter out. Then, wash the filter under warm water, scrubbing gently. Reinstall once cleaned. 

3. Clear the Garbage Disposal 

Because an overfilled disposal can force foul-smelling wastewater back into the appliance, run the disposal to ensure it’s entirely clear of any food debris. 

4. Inspect the Air Gap and Drain Hose

Check the air gap on your dishwasher (usually located on the sink) to confirm it’s not clogged. Afterwards, examine the drain hose for any kinks of blockages. 

5. Inspect the Drain Pump Impeller 

Next, locate the impeller at the base, ensuring it turns smoothly and is free from any obstructions. 

6. Use an Odor Neutralizer

Finally, once you’re sure that all parts of the dishwasher have been successfully cleaned, run the appliance on an empty cycle with a specialized dishwasher odor neutralizer. 

FAQs Why Does my Dishwasher Smell Like Rotten Eggs

Can you use bleach to clean a smelly dishwasher? 

Although bleach can be effective against mold and mildew, avoid using it in stainless steel dishwashers as it can tarnish and corrode the interior. 

What cleaner to use for a smelly dishwasher? 

A simple combination of baking soda and white vinegar can effectively eliminate unwanted odors. Many commercially available dishwasher cleaning agents are specifically designed to tackle residual buildup and foul smells. 

Can you run the dishwasher with vinegar? 

Absolutely. Vinegar is a perfect tool to help remove mineral buildup and neutralize odors. Simply fill a bowl with white vinegar, place it on the bottom rack, and run a full cycle. You’ll be pleased with the results! 


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Having renovated two homes and completed countless repairs, it was time to share this experience with the world. From repairing kitchen appliances to remodeling entire homes, my 30 years of experience will hopefully help you on your journey to a beautiful and functional home