September 26, 2023
Why Does My Humidifier Smell: Helpful Tips & Recommendations

Why does my humidifier smell like fish or urine

Humidifiers are great tools not only for improving the air quality, but also for adding a pleasant smell to your room. However, sometimes instead of a nice aroma it might produce a strange smell that reminds you of fish, or even urine.

If your humidifier smells bad, you might inspect it for some potential problems.

Some of the most common questions when using a humidifier are:

– How do you get the smell out of a humidifier?
– What do I do if my humidifier smells like mildew?
– Can you use tap water with a humidifier?
– Will a humidifier make a room smell?

If you have any of the following questions, then keep on reading to find the answers.

why does my humidifier smell

Types of smells that your humidifier can emit

An unpleasant smell of fish or mildew

Humidifiers can smell like fish because of mildew or mold. Water is a breeding ground for bacteria, so such problems can easily occur without frequent cleaning.

In some cases, there can be no actual mold and the humidifier is smelling because it is unclean.

The best solution to this problem is deep cleaning the device.

Cleaning all parts of the device carefully with some additional bleach in the water can help combat all the built-up harmful bacteria that can make your air smell like fish.

You should never forget to regularly rinse the water filter and water tank of your device. The best way to go is to soak each element of the humidifier in hot water with a dash of bleach.

Pay special attention to the filter, if it’s too dirty, it cannot function properly. If you use your humidifier daily, the filter should be changed every two months, if you don’t use your device often, it’s possible to change it every three to four months.

Cleaning is important not only because of a potentially unpleasant smell and bacterial growth inside the humidifier, but also because of the health risks that can appear if your device disperses mold spores into the air. So it’s better not to risk your own health and keep an eye on your device.

Mineral deposits and stagnant water can make your humidifier smell like urine

Not only bacteria or mold can make your humidifier smell bad, the quality of water should be considered too. An odor that smells like urine might be caused by the water quality or hard water.

Most people use tap water in their humidifiers. While tap water is safe for drinking in most places, it still contains minerals in it.

Mineral deposits can result in a build-up of different minerals, such as calcium or sulfur, inside the humidifier, which might result in a urine-like odor.

Other signs of a mineral build-up are white scale in the water tank or reservoir. If you see that they look whitish, then you should check your water quality.

To solve this problem, you should deep clean the device and its parts. In more severe cases, the parts of the humidifier should be soaked in water for a couple of hours to get rid of the scale.

If you filter your water before adding it to the water tank or use distilled water, it will help you with unwanted odors.

For preventive measures, use only distilled or purified water that should be changed regularly. Stagnant water can encourage mold growth. So it’s very important to keep humidifiers and the water in them clean to never experience a urine smell.

It should be noted that you shouldn’t just add fresh water to the already presented in the tank. First, empty the tank, then refill it with fresh filtered water.

Burning smell

Sometimes a humidifier smells of burning, that usually reminds of the smell of burning plastic. In this case, it is important to consider how new the device is. If it is new, then the problem should go away after a couple of uses because it still can have some residue from the production.

If plastic off-gassing doesn’t go away in about three to four days of consistent use and the humidifier still smells, you should address the technical part of it.

If it has already been in use for quite some time, and it smells of burning plastic, the issue might be more serious. You should examine the power cord to see if it has any kind of damage and fix it.

The issue might be caused by a particular power outlet, so changing the outlet of choice can also help.

In general, a sign of overheating should be concerning. Check if there is enough water in the tank, if there are any leakages, and if the latter is confirmed, immediately disconnect the humidifier from the outlet.

And if you have a portable humidifier that doesn’t need a lot of energy, you should definitely check it for leakages because overheating is not natural for such small devices.

Incorrect use of essential oils

One of the mistakes that many people make that causes a humidifier to break or not work properly is the use of essential oils, or more precisely, adding them into the wrong compartment. You should never add essential oil straight into the water reservoir.

Oil doesn’t mix with water; therefore, it clogs up the waterway, which may lead to stagnant water and a urine-like smell and eventually break your device.

If you want to add a fragrance directly into water, a perfume that is not oil-based is a good way to go. Just spray a little bit into the water of your humidifier.

What else you can add into your humidifier

Bleach and hydrogen peroxide

As a way of disinfecting the air and keeping the bacteria and mold in your device at bay, you can add a lit bit of bleach or hydrogen peroxide to the water reservoir. However, it is highly important not to add too much, since it can result in a strong smell that can lead to headaches. Just a dash will do the job.

Lemon scent

A similar effect can give a touch of lemon scent, which not only has a refreshing smell but also has antibacterial properties.

Adding a lemon scent or alternatively some vanilla extract can also help with making the room smell like a fresh garden, but remember not to put it directly into the water tank since it contains oil.


Another mold inhibitor that you can put into your humidifier to combat bacteria and mold is vinegar. A good idea is to add distilled white vinegar, but just a little bit so that the smell of vinegar doesn’t become too overpowering.

Baking soda

Baking soda is a good ingredient to remove an odor and bacteria too, but you should be careful with it since it is abrasive and can damage the device when used in excess.

It’s a good idea to check the manual for your humidifier first before adding anything into it

Essential oils

Good quality essential oils are a great way to make your humidifier smell great and to disinfect the humidifier itself.

Many essential oils have antibacterial and antimicrobial properties, so adding a couple of drops into the right compartment can be quite beneficial, and you won’t ever see mold or have a terribly smelling humidifier.

Some of the oils you can use are peppermint, lemongrass, clove, or lavender, but you are not limited to these, you can find hundreds of different types on the market.

Types of humidifiers


Humidifiers come in different forms and sizes. When it comes to its sizes, there are portable humidifiers and whole-home devices.

A whole-home unit cannot be transported, and it humidifies the entire house, while portable ones are easy to carry around.


In terms of technology, humidifiers can be divided into warm mist humidifiers that emit hot and sterile air and cool mist humidifiers that produce cold and filtered air. Both types should always be kept clean.

How to use a humidifier

Humidifiers are amazing gadgets that can make our life easier, especially for those who have respiratory problems. Thanks to a humidifier, it is easier to maintain humidity levels in the room.

They also make our homes more comfortable by adding pleasant smells.

A nice-smelling room plays a big role in making our homes cozier.

As a rule, a humidifier should not be in the direct vicinity of a person, so it’s better to keep it about three feet away from the person. Being too close to the humidifier can be harmful.

You also shouldn’t keep your humidifier turned on for too long, too much humidity becomes as bad as excessive dryness of the air. When there is too much moisture in the air, it can lead to growing mold in your house.

When you want to use a humidifier regularly, you might want to use a hygrometer to measure humidity in the air.

What effect humidifier has on the air quality

A humidifier doesn’t really reduce any particles in the air or eliminate an odor. It simply releases water vapor into the air, which raises the humidity level because it can add moisture into it.

If it has essential oils in it, it can fill a room with a nice aroma, but it mostly masks any bad smell. Although some types of humidifiers can filter the air and remove smells. It depends on the humidifier’s model, so if you have particular preferences as to what your humidifier should do, check out different types and models and compare their functionality.

Summary of the reasons for smells

If you’re asking yourself “Why does my humidifier smell”, and if it has a musty smell, a fish or urine smell, you should consider the following possible issues:

  • Mold or mildew inside the humidifier
  • Scale caused by unfiltered and stagnant water in the humidifier with mineral deposits like sulfur in it
  • Overheating or general electricity-related problems
  • Adding essential oils straight into the water reservoir

Some rules for using a humidifier

If your humidifier smells bad, and you’ve identified the underlying reason for it, stick to the following general rules for keeping your device well-functioning and getting the most out of its use:

  • Change water daily
  • Don’t forget to clean and change the filter in the humidifier
  • Fill your humidifier only with distilled water or filter your tap water
  • Clean the humidifier regularly with some cleaning agent
  • Add vinegar, vinegar solution, hydrogen peroxide, or bleach into the water reservoir
  • Add essential oils only in the special compartment


Most importantly, your humidifier should be cleaned regularly. A dirty humidifier is worse than having none.

Adding mold inhibitors like baking soda, bleach, white vinegar, or hydrogen peroxide in distilled water and cleaning all the parts separately is a good way to maintain beneficial properties of a humidifier, prevent bacteria growth, and never encounter unpleasant musty smells.

For a nice-smelling room, use essential oils, but remember to add them into the right compartment. And clean water is a must.

The functionality of your humidifier depends on your maintenance of it, so don’t forget that its functionality results not only in the smells but also in possible negative effects on your health.

If you follow all these rules, you most definitely will be able to enjoy your humidifier that has no nasty urine, fish, or musty smells.

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