Why Does Humidifier Filter Get Crusty (Simple Fix)

  • By: madison
  • Date: November 24, 2022
  • Time to read: 8 min.
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Do you own a humidifier? Do you ever notice that it gets a bit crusty at the top of the filter? Well, you’re not alone. Unfortunately, this is a pretty common problem for humidifiers.

Humidifiers are a great way to help keep your home comfortable. But when you’re using your humidifier, you might notice that the filter gets a little crusty. Why this happens and how you may avoid it from happening again.

In this blog post, we’ll talk about the causes of a crusty humidifier filter and how to prevent it from happening again.

Key Takeaway’s

  • A humidifier filter can become crusty for a few reasons, including high mineral content in the water, build-up of bacteria or mold, or not being cleaned regularly.
  • High mineral content in the water can cause the filter to become clogged and coated with minerals, which can then lead to bacteria or mold growth.
  • Not cleaning the filter regularly can also lead to a build-up of dirt, dust, and other contaminants that can cause bacteria or mold growth.
  • Regularly replacing the filter and properly cleaning the humidifier can help prevent these issues and keep your humidifier working properly.
Why Does Humidifier Filter Get Crusty
Why Does Humidifier Filter Get Crusty

The Reason Why The Humidifier Filter Gets Crusty

The mineral build-up from tap water leaves a film of calcium on the filter that turns it white and looks like a skeleton. When this happens, your humidifier can’t do its job. 

The filter’s moisture attracts debris, and when the pad dries, it leaves behind a hardened mineral residue. This residue might harden and grow crusty over time. 

If you’ve noticed crusty white material appearing inside your humidifier, don’t worry. It’s probably just mineral deposits from your water. The tank in your humidifier acts as a small reservoir, and over time, minerals will collect at the bottom of the tank.

What Are The Causes Of A Crusty Humidifier Filter?

What Are The Causes Of A Crusty Humidifier Filter
What Are The Causes Of A Crusty Humidifier Filter

The humidifier filter is one of the essential parts of your humidifier. It catches any debris and impurities floating in the water, preventing them from entering your air. 

This can lead to accumulation, giving the filter a crusty or foggy appearance. 

Water Reservoir 

The water reservoir is where you fill up your humidifier with water. If it isn’t clean, minerals can build up on the walls and inside the tank. 

This will cause a build-up of hard water deposits called limescale, affecting your humidifier’s performance and appearance and crusty filter. 

Mineral Build-up 

Calcium and magnesium are minerals found in hard water – both of which can build up on the surface of your humidifier over time and interfere with its filters’ ability to trap pollutants. 

Mold Spores 

When mold spores get into your humidifier, they may clog its filters or create mold growth on its exterior. This is another cause of crusty humidifier filters.


Fungi such as mildew may also grow in your humidifier if it becomes contaminated by mold spores or other contaminants. 

Improper Cleaning

A crusted filter indicates improper use or damage to the filter material itself; this usually happens when someone tries to clean their filter too aggressively without taking care not to damage it further.

How Do I Prevent A Humidifier Filter From Getting Crusty? 

How Do I Prevent A Humidifier Filter From Getting Crusty
How Do I Prevent A Humidifier Filter From Getting Crusty

There are some simple steps you can take a right at home to help prevent a crusty humidity filter from forming on top of your unit: 

Keep Your Unit Clean 

Regular cleaning keeps dirt and dust out of the unit.

Keep Your Tank Clean

Regular cleaning helps keep mineral deposits off the heating element. 

Prevent Contaminants From Entering Your Unit

If possible, avoid letting impurities get into the humidifier water. Ensure the input air duct is well maintained to prevent impurities that may get inside the humidifier and don’t come out. 

Use Cleaner Water

Using filtered tap water instead of untreated tap water will help reduce contaminants keeping moisture levels high. Using distilled water also minimizes what may cause mineral deposits on the humidifier filter and form the crust. 

Properly Maintained Units

Correctly maintained units will produce higher-quality air. Also, reduce crusty humidifier filter issues. In addition, regular maintenance includes cleaning all filter surfaces, especially the humidifier water filter. This should be done at least once every six months and more frequently if necessary.

Keep Your Unit Ventilated

Opening windows does not efficiently allow fresh air into your unit, causing humidity levels outside to rise. In addition, improper maintenance can lead to problems with other parts of your system.

Is It Safe To Use A Crusty Humidifier Filter? 

Is It Safe To Use A Crusty Humidifier Filter
Is It Safe To Use A Crusty Humidifier Filter

There is usually some risk when utilizing a crusty humidifier filter that has been ignored over time – mainly if it includes mold spores or other dangerous substances. 

While there is no definitive answer as to whether this type of situation is safe, what we can say is that it should only ever be considered as an absolute last resort option where no other alternative exists. 

This is due to potentially serious health implications associated with poor quality air circulation and breathing in these contaminants at close quarters regularly. 

If you find yourself in this position, the first thing you should do is to check with customer service at your local appliance store for advice on how best to proceed from here.

If ultimately they suggest continuing using it despite its current state, then make sure you take extra care. For example, avoid coming into direct contact with any contaminated areas (such as wearing gloves) when operating it. 

And finally, keep an eye out for any signs of symptoms related to exposure over time (such as coughing or sneezing) and seek medical help if necessary.

Tips For Cleaning Crusty Humidifier Filter

The first step is to verify if the crustiness on your humidifier filter is due to calcium deposits. If it is, you will need a different cleaning solution than if other substances cause the crustiness. 

If the crustiness appears to be calcium deposits, you can try using a toothbrush and undiluted white vinegar to scrub away the build-up. Be careful not to damage the wick while doing this. 

After you’ve gotten rid of as much debris as possible, rinse the filter with water and let it dry before placing it back in place. If there are still some areas that seem stubborn, use a disinfectant such as bleach to remove them.

Can A Filter Get Crusty If There Are No Mold Or Bacteria In It?

If you notice your humidifier’s filter is starting to get crusty, it may be because there is gunk in your water supply. Even if your humidifier has no mold or germs, this can happen.

To clean your humidifier’s filter, you’ll need to empty the water tank and remove the filter. Then, soak the filter in a water solution for about an hour.

After that, you can clean the filter with a sponge or clean cloth. If the filter is still crusty, you can try soaking it in a solution of soda and cool water. This should help remove any odors from the filter.

Do I Need To Replace A Crusty Humidifier Filter? 

Yes, you will need to replace your crusty humidifier filter. But, if it’s possible to clean the crust off effectively, you can keep it for a while before replacing your filter.

The filter on most humidifiers has to be updated every three to six months. The filter’s job is to filter out pollutants like minerals, germs, and mold from the water.

If the filter isn’t replaced, these impurities can be released into the air and the water vapor, which can cause health concerns, an unpleasant odor, and damage to the humidifier.

  • If you’re not sure when the filter was last replaced, it’s probably time to replace it.
  • Filters are relatively inexpensive, and replacing them is a quick and easy next step for homeowners.
  • There are a few various humidifiers, and the type of filter you require depends on the type of humidifier you have.

Benefits Of Cleaning The Crusty Humidifier Filter

Benefits Of Cleaning The Crusty Humidifier Filter
Benefits Of Cleaning The Crusty Humidifier Filter

Cleaning the crusty humidifier filter can have many benefits. A clean filter can help improve the quality of the air in your home, and it can also assist in extending the life of your humidifier.

A clean filter can help reduce the amount of noise that your humidifier makes. In addition, cleaning off the crust can improve humidifier efficiency and lower the humidifier’s energy usage.

Will Cleaning Crusty Humidifier Filters Improve Its Performance?

Cleaning crusty humidifier filters can improve the performance of your humidifier. However, it is essential to note that you should never use harsh chemicals or abrasive materials to clean your humidifier filter.

Additionally, you should always make sure that the filter is completely dry before using your humidifier. Although, all in all, cleaning crusty humidifier filters can be beneficial, you should clean them when cleaning becomes not only necessary but also regularly.


If you’re like most people, you cringe when you see a crusty humidifier filter. The thought of dealing with that disgusting build-up is simply unacceptable.

Unfortunately, if you don’t take proper care of your humidifier, it will eventually start looking and performing like that. This blog post examined the most common reasons humidifier filters grow crusty and provided recommendations for cleaning them.

We have also included a few preventive measures that can help keep your humidifier running smoothly for years to come!

Frequently Asked Questions

Can I use bleach on my humidifier filters to keep them from getting crusty?

Bleach can be a helpful cleaning agent for humidifier filters, but it should only be used under the guidance of a professional. Using bleach on humidifier filters could potentially damage them and result in an unpleasant odor.

Do all filters for humidifiers get crusted over time?

No, not all humidifier filters will become crusty over time. We need to know how often your humidifier is used to answer this question.
 Some filters may need to be replaced more frequently than others, but there is no one-size-fits-all answer for filter cleaning.

Can I Clean a Humidifier Filter Using a Water Softener?

One should not clean humidifier filters using water softeners. These cleaners remove hard water deposits and mineral build-up, damaging humidifier filter material. Instead, you should use a mild dishwashing detergent or bleach solution regularly.

Can I Clean a Humidifier Filter Using a Washing Machine?

People do not recommend washing humidifier filters in a washing machine. Washing them with the device can cause damage to the filter, and high-pressure cleaning can void the humidifier’s warranty. Instead, use a sponge or small brush to clean the humidifier filter material.


Kenneth Sine
Kenneth Sine

My name is Kenneth Sine, and I’m a product engineer who has been working with humidifiers for over ten years now. In my spare time, I write for HumidifierSource.com, where I share my knowledge with others who want to learn more about the world of humidifiers.