Pink Mold And Residue In Humidifier? How To Clean It

Although humidifiers improve the air quality inside your house by adding moisture to the atmosphere, a moldy humidifier will actually deteriorate the air quality.

Pinkish slimy substances start to accumulate inside a humidifier due to the availability of water there. This slimy substance is mold and it’s pink because of the pink to reddish pigmentation found in its forming microbes.

The presence of this type of mold isn’t always apparent and completely getting rid of it requires some tricky measures. So, what should we do about the pink mold and residue in the humidifier? How to clean it properly? Is it too harmful? 

For your convenience, I’ve scoured the internet and gathered all the necessary info you need about molds and residues in humidifiers and how to get rid of them properly. Let’s dive in.

Pink Mold in Humidifier: What Is It & Is It Dangerous?

Let’s talk about what it is first, and we’ll dive into its harmful effects later. Technically, all variants of pink mold aren’t real mold.

The term mold includes all classes of microscopic fungus, and pink molds aren’t always classes of fungus. Some pink mold denotes the invasive growth of certain kinds of water-borne bacteria, which has a similar infestation pattern to mold.

They’re specifically called pink molds because of their pinkish-white color and mold-like growth pattern.

Pink mold thrives in damp and dark areas. Besides the damp interior of a humidifier, pink mold also invades washroom sinks, basins, kitchen windows, clothes, etc.

Pink Mold Types

Mainly three variants of pink molds are seen around households –

  • Serratia Marcescens

This is a pink, rod-shaped bacteria that highly prefers damp environments for their growth. In the human body, this pathogen is responsible for various wound infections, urinary tract infections, and nosocomial infections.

This type of mold is most seen in toilets and showers because it feeds on soap and shampoo residue. It’s also found in damp and dirty environments. If your humidifier hasn’t been cleaned for a good amount of time, this mold has definitely reigned throughout.

  • Aureobasidium pullulans

This sort of mold is actually an ‘A’ class of contaminant fungus. It’s ubiquitously known as harmful to nature and can cause various sorts of problems.

Besides damp areas, this mold also grows on organic surfaces like plants and wood. It has sort of a pink-bluish color and infests humidifiers quite often.

  • Fusarium

Unlike the other two, this type of mold isn’t just a single class of organisms but rather a cosmopolitan family of imperfect fungi. Also, these variants are eminent for their alarming rate of growth.

Fortunately, their infestation is limited to plants and other organic surfaces, so they are barely seen in households. The only way they can invade your home is by indoor plants.

How Dangerous Pink Mold in Humidifiers

You should know that pink mold is nowhere near as deleterious as black and green ones. And for any pink mold infestation, whether it’s in your humidifier or somewhere else, you can take care of it on your own—no need to call the professionals.      

Let’s take a look at how different types of pink molds can cause you harm.

  • Serratia Marcescens

Infestation of S. marcescens occurs if you leave your humidifier too long without proper maintenance. And you won’t have to worry about breathing the spores, but if the humidifier was dirty enough to grow this variant, many other inimical microbes might have infested.

But problems occur if S. marcescens can reach any wound. The wound is bound to become a festering infection. And this variant also induces many other types of infection.

  • Aureobasidium Pullulans

A. pullulans form the most in humidifiers and cause various irritation and symptoms. Breathing in its spores can cause various respiratory conditions like cough, blocked nose, wheezing, sneezing, and many others.

Moreover, there is a specific acute lung condition named ‘Humidifier fever’ that is the direct result of pullulans spores from humidifiers. The condition involves acute cough, fever, and dyspnea. 

Such spores also severely worsen various predated respiratory conditions like asthma. So, if you already have respiratory conditions, avoid inhaling spore-infused air from humidifiers at all costs.

  • Fusarium

This type of mold will rarely find its way into your home let alone the humidifier. Even if it reaches you, it can’t thrive in a strong immune system.

But for people with a weak immune system, it’s a grievous threat. Fusarium mainly invades your body via food colonized by it. It can cause mycotoxicosis as the family of microbe forming Fusarium generates various toxins inside the food.

These toxins cause nausea, vomiting, and other gastrointestinal disturbances. It can also get into your body through your eyes and nails, causing various dangerous infections.    

Pink Residue in Humidifier: What You Need to Know

Although different variants of pink mold are seen in households, mostly ‘A’ pullulans form inside your humidifier. Other variants might also accumulate inside and across the body of the humidifier, but it does so only if you don’t keep the humidifier clean.

Sadly, there is no way to stop the forming of ‘A’ pullulans in your humidifier. One reason is that humidifiers are mostly used for creating a cozier sleeping environment by creating moisture and removing dust. Well, people often ask, do humidifier help with dust? Yes, they do.

So, humidifiers often function in a dark and dusty environment. And as a humidifier requires water in its water tank to function, the dark, dirty, and damp environment is just the perfect place to grow this specific type of mold.

Another reason is the quick proliferative ability of the fungus. Your humidifier might have layers of mold present in its water tank within one or two days of usage.   

And the required time depends on the quality of the water. If the water is clean and distilled, a mold layer will form slowly. Although its forming is inevitable, the right type of water can slow the process a bit.

Getting Rid of Pink Mold from Humidifiers

Pink mold in humidifiers isn’t always vivid because sometimes the infestation can be white. But you’ll have to remember even though your air purifier is a mold killer of some sort, the mold infestation in your humidifier is bound to happen sooner or later.

So, even if it doesn’t look like it, you must get rid of the accumulated mold of a humidifier at regular intervals. Let’s take a look at a step-by-step guide regarding how to get rid of pink mold in your humidifier.

  • Assembling the Cleaning Agents

You can simply detach your water tank and wash it with water and soap, but it will never be enough to destroy the mold colony. To completely eradicate the mold, you’ll need some specific cleaning agents.

It’s better if you can manage hydrogen peroxide, but vinegar would do just fine. If you haven’t cleaned the machine for a while, consider getting some bleach as well.

However, before using harsh chemicals like bleach, make sure it’s safe for your appliance by reading the user manual. 

  • Get the Water Tank Ready

You’ll mostly need to wash the water tank of the humidifier to get rid of mold. So, unplug your machine and detach the water tank. Throw away any residual water from it. 

  • Soak the Tank

After emptying the tank, fill it with vinegar or hydrogen peroxide. Let the tank sit for about half an hour. This will loosen the mold so you can wash it off easily.

If you wish to use bleach, use it beforehand. Don’t mix bleach with vinegar or hydrogen peroxide because the resultant chemical might turn out to be harmful.

  • Washing the Tank

After the tank sits in the agent for half an hour, empty it. Then rub the pink residue off using warm water. Before you re-attach the tank, make sure it has dried completely.

  • Finish with Cleaning the Base     

After finishing the water tank, clean the base with a diluted vinegar or peroxide solution. Make sure you read the instruction manual beforehand. Not a single drop of liquid shouldn’t go somewhere it isn’t supposed to.

That’s it. You’ve done it! Now before putting everything back, check the vapor spout. If it seems moldy, use the light solution you used for the base here as well. 

Frequently Asked Questions

  • How to slow down the pink mold infestation in a humidifier?

Use clean distilled water instead of tap water. You can also add a very small amount of vinegar or peroxide to the water. This is very effective at keeping molds at bay.

Tap water is full of different minerals and other microbes, which expedites mold infestation. Thus, using the right type of water in humidifier is extremely important.

  • Can babies get sick from humidifiers?

If the humidifier doesn’t contain any mold growth or bacteria invasion, then the baby would be just fine. Babies get sick due to dirty humidifiers.

Some spores emitted from a dirty humidifier can be totally ineffective to an adult while causing various flu-like symptoms in a baby. So, if you’ve got babies, be extra cautious with your humidifier.


So, this article helped you gather the necessary information on pink mold and residue in humidifier and how you can clean it properly.

Remember, there are countless benefits of using a humidifier, but it can also be a source of countless ailments and irritations if neglected and not properly maintained.

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Billy J. Weber

Hi. It’s Weber, founder and author of this site Currently you are reading. I am dedicated to provide valuable insights and practical tips to air enthusiasts and anyone interested in improving their indoor air quality.

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