There’s mold in my dishwasher! Find out what’s causing it and how to clean it

Written by Adam Morris
6 Min read
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Mold problems in a dishwasher

Did you know that the humble dishwasher has actually been around for over 170 years? First patented in 1850, the very first dishwashing prototype was a wooden box that relied on a hand-turned wheel to splash water on dirty dishes.

A more modern dishwasher – one using water pressure to clean and that more closely resembles the machine we use today – was patented in 1886 by a socialite who was so fed up with washing dishes by hand, that she decided to invent a solution herself.

Things have certainly changed since then, and during a recent survey by Beko 10% of people stated they now couldn’t live without a dishwasher, but we think this number should actually be a lot higher! Who wants to stand for hours, elbow deep in dirty water scrubbing pots and pans?

One of the main problems is whilst it’s great at getting your plates sparkling clean, it’s a damp and dark enclosed space that’s a breeding ground for mold. We’re going to tell you exactly why this mold keeps appearing and what you can do about it.

How to tell if there’s mold in a dishwasher

According to a Medical Mycology study, over 62% of all dishwashing appliances across six continents had some kind of fungal growth, ranging from mildew and yeasts to some more harmful types.

In order to determine if your dishwasher has mold you should look for discoloration and a slimy residue, there’s also likely to be a strong musty smell when you open the door.

Leftover food in a dishwasher will start to grow mould within just a few days and will be quite easy to spot, but you should also check in corners and along the rubber gaskets.

Your dishwashing appliances filter is likely to have some build-up, but this doesn’t mean it’s moldy. However, if the housing around the filter is black then you can assume it is moldy.

If you suspect your dishwasher is moldy you should wear gloves and goggles before carrying out any checks. Mold spores can be dangerous

Mold in dishwasher

What causes mold in a dishwasher?

Your appliance has to deal with a whole load of leftover food, sauces, grease, and grime on a daily basis, so it’s no wonder mould grows freely there if things aren’t kept in check. Over time, food particles get trapped in the crevices and hidden areas of your appliance, often going unnoticed until it causes problems.

In order for mold to grow it requires an environment with certain conditions it can survive in:

  • Temperature – most molds cannot grow in temperatures below 40 degrees Fahrenheit and grow best between 77 and 86 degrees, especially if humid
  • Water – if the conditions are damp, humid, and wet then mold will thrive.
  • Oxygen – molds are obligate aerobes which means they need oxygen to survive – they can survive even when oxygen levels are very low
  • Food – mold grows on materials it can digest and can metabolize almost every organic matter in nature

Most common places for mold to build up in a dishwasher

  • Dishes and dishwasher rack
  • Vent
  • Drain hose
  • Behind the dishwasher
  • Door seals
  • In and around the soap dispenser

Can mold in an appliance make you sick?

Most people don’t realise that the mold in their dishwasher can make them sick! Molds are a form of fungus and are found in numerous places all over the world. It is generally harmless, but when it grows in smaller enclosed spaces it can present a serious health risk.

As mold grows, spores, cells, fragments, and unstable organic compounds can enter the air. These can produce allergens and irritants, some of which can be toxic, especially to those people who have a sensitivity to them.

Some of the most common health issues include:

  • Breathing problems – mold particles can irritate the lungs, nose, and throat and is particularly troublesome for anyone with an existing breathing problem such as asthma
  • Allergies – some people are allergic to mold particles and will react when they come into contact with them
  • Aspergillosis – some types of mold can cause a serious health problem called aspergillosis in people, especially those with a weakened immune system

What types of mold are most likely to grow in a dishwasher?

Black mold

Black mold generally appears on food or as mildew around the drain, vents, and door seals.

Orange mold

Orange mold is called Biofilm and is often mistaken for rust. It’s generally not harmful but immune-compromised people and children can be susceptible to infections so it shouldn’t be ignored

Pink mold

Pink mold is a sign of bacterial mold and generally appears as pink slime. It can be difficult to eradicate these fungi once they’ve started growing and can be a cause of food poisoning.

How to clean mold from a dishwasher

  1. Take out all the shelves, trays, and filters from the dishwasher and wash them all separately in the sink with a scrubbing brush and a mixture of vinegar, baking soda, and water, removing all traces of food or mold from them.
  2. Once clean wash again with warm water and detergent
  3. Put the filter and shelves back into the dishwasher
  4. Fill a cup with vinegar and place it on the top rack of the dishwasher
  5. Put your dishwasher onto the hottest and longest cycle, letting the vinegar get to work – vinegar has antifungal and antibacterial properties and is a cheap and effective treatment for many types of mold
  6. Sprinkle a cup of baking soda on the bottom of the dishwasher and set it again to run a short but hot wash
  7. Allow your dishwasher to fully dry before using it again

Top tips for preventing mold in an appliance

To discourage mold growth, try these handy hints:

  • Keep your appliance door open a small crack when not in use
  • Leave the appliance door fully open for one hour after emptying a clean cycle of dishes.  This will allow the appliance to completely dry, making it more difficult for mould to grow
  • Thoroughly clean your dishwasher once a month, paying especially close attention to the rubber parts of your machine, including the seal around the door
  • Control the humidity in your kitchen and make sure your kitchen is well ventilated with an exhaust or fans.
  • Most dishwashers share a drain with a kitchen sink, so if you have a garbage disposal unit make sure you run it and that it’s empty before you turn on the dishwasher
  • Use a long, hot setting whenever possible. Cold and abbreviated cycles produce sludge and slime build-up
  • Use the heated dry option whenever possible
  • Consider using liquid detergent over detergent pods as pods often don’t clean quite as well during cooler cycles as the water isn’t hot enough to dissolve the pods
  • Clean your filters daily – think of your dishwasher filter as your kitchen drain. The water used by your dishwasher has to move through this filter, so keeping it clean is essential to clean and mold-free usage
  • Run a cup of white vinegar through the dishwasher on a long and hot cycle once a week to disinfect it and naturally remove any limescale build-up
  • If you notice mold in your dishwasher even after cleaning, there may be an issue with the drain line. Ask an appliance specialist to give it a check-over and to investigate any larger problems

Final words of advice

Whilst dishwashers have saved families from hours of manual labor, they’ve caused extra work and a potential health risk in return! Dishwashers provide the ideal growing conditions for mold and because of all the different moving parts and accessories, it can be difficult to see exactly what is going on inside. 

However, with just a little bit of time, care, and attention you can stop the risk of mold to you and your family and make sure your dishwasher remains one of the most-loved appliances in your home.


Is it safe to use a moldy dishwasher?

Whilst the majority of molds are not harmful to health, it’s worth remembering that as mold grows, spores, cells, fragments, and unstable organic compounds can enter the air. These can produce allergens and irritants, some of which can be toxic, especially to those people who are sensitive to them.
If you have noticed mold in your dishwasher, it is always better to clean and sanitize it before using it again, those few minutes of effort could stop you or someone in your family from getting sick

Why is there mold growing in my dishwasher?

Dishwashers provide the ideal growing conditions for mold, and without regular cleaning and maintenance, you will inevitably notice mold growing over time. There are a number of ways you can prevent the growth of mold, including:
·       Clean the filter every day
·       Allowing the dishwasher to fully dry after every cycle
·       Using lot and hot cycles whenever possible
·       Cleaning the inside with white wine vinegar and baking soda

What happens if I breathe in black mold?

Some people may have an allergic reaction to mold if they accidentally breathe it in, displaying symptoms such as a runny nose, sneezing, watery eyes, and a skin rash. Those with existing breathing problems such as asthma may experience breathing problems.

When should I replace my dishwasher?

According to manafacturers, the average dishwasher should last around 10 years before it needs replacing. However, a recent investigation revealed that around 25% of dishwashers either broke or stopped working as well as they should within five years of purchasing.
Some of the most common signs your dishwasher may need replacing include:
·       Your dishes no longer come out scorching hot
·       You can see flecks of rust inside
·       The door latch stops working
·       It doesn’t drain properly
·       It’s not energy efficient

Appliances made simple. 

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