The white substance in your humidifier is the build-up of mineral deposits from calcium and magnesium in tap water. These minerals form deposits also known as limescale. Humidifiers can also release a white dust from these minerals in the mist that is dispersed across your room and furniture.
If you’ve noticed some white stuff in your humidifier or settling on the ground and furniture around it, you might be worried your air isn’t that safe to breathe or that there’s something wrong with your humidifier.
In this guide, we cover the reason why there is white stuff in your humidifier, how to remove it and how to stop it from happening again.
What the white stuff in your humidifier is
The tap water (or well water) in most households contains the minerals:
- calcium
- magnesium
- potassium
Calcium and magnesium are a major ingredient of hard tap water, and with more than 85% of American homes being supplied hard water it’s no surprise these minerals are popping up in your humidifier.
The white stuff forms slowly over time in your humidifier when you regularly use tap water to fill up the reservoir.
It can cause white stuff to build up in the water tank, but also in the outlet. Then when you use your humidifier a fine white dust is released around your home.
The accumulation of these mineral deposits is also known as calcification or limescale.
Other possible (although unlikely) reasons why there is white stuff in your humidifier include:
- Infrequent changes of the water in the humidifier
- Damaged or clogged filter (if your humidifier has one)
- Improper storage of your humidifier when not in use
Humidifiers can also develop a pink residue, especially in or around the water reservoir and outlet. Plentiful Air has detailed information on how to prevent this common problem available here.
How to remove the white stuff
The white calcification deposit can be inside the humidifier tank and the tube or hose that draws water into the device.
You might also notice the white substance on other sections of the humidifier, like the outlet.
To decalcify your humidifier, follow these steps:
- Turn off and unplug the humidifier
- Remove the residual water in the humidifier tank or reservoir
- Disassemble your humidifier
- Soak the humidifier tank in a mixture of 2 tablespoons of vinegar and half a liter of water for 20 minutes
- Discard the white vinegar and scrub the humidifier tank with a soft brush
- If you notice white stuff on other parts of your humidifier that you can’t soak in water, put a soft cloth in the white vinegar solution and place the cloth on those areas for about 20 minutes.
- Rinse the humidifier tank with clean water until the vinegar smell is completely gone
- Wipe the rest of the humidifier with a clean soft cloth
- You can rewash the humidifier tank with clean water and mild soap to ensure that the vinegar is properly rinsed off the tank
- Fill the humidifier tank with distilled or demineralized water (or at least softened water)
- Plug in and switch on the humidifier for use.
4 ways to prevent white stuff in your humidifier
There are four easy options you can choose to prevent a build up of white stuff in your humidifier:
1. Use distilled water
Distillation is a water purification method that reduces the mineral content of water. When you replace hard tap water with distilled water in your humidifier, the almost complete lack of minerals mean white stuff (calcium carbonate) will not form in your humidifier.
You can either invest in a water filter system for your home – a simple water filter pitcher will do, or you can buy distilled water by the gallon.
2. Use a de-mineralization cartridge or filter
A demineralization cartridge can trap the minerals in water and prevent them from undergoing any form of breakdown followed by release into the atmosphere. The efficiency of this method depends on the mineral content of your water, and the design of the cartridge or filter.
This method is mostly applicable to ultrasonic humidifiers.
3. Use a cool mist humidifier
A cool mist humidifier is designed to operate differently than the ultrasonic or impeller humidifier. They don’t tend to trap minerals or release white dust.
The appeal of ultrasonic humidifiers over these humidifiers is the absence of a fan which makes it extremely quiet. If you don’t mind a little noise while running your humidifier, then you should invest in cool mist humidifier models.
4. Use a water softener
The root cause of mineral deposits in your humidifier is hard water. If you don’t have access to distilled water for your humidifier, you can use a water softener system to reduce the mineral content of your water.
This will serve your humidifier as well as other home appliances like a washing machine, but is a more expensive solution.
Types of humidifiers that leave white dust
Humidifiers can be ultrasonic, warm mist, cool mist, ultrasonic evaporative, impeller cool mist, or steam vaporizing.
The engineering technology of these humidifiers determines the amount of minerals and microorganisms dispersed from each one.
According to the US Environmental Protection Agency (EPA), ultrasonic and impeller humidifiers are the only kind of humidifiers that are known to produce white dust.
- Ultrasonic humidifiers produce either warm or cool mist with a metal diaphragm subjected to high frequency and sound vibrations. The sound vibrations spray out water molecules in the form of mist that contains all dissolved minerals from the water.
These minerals then produce white dust that settles on furniture, countertops, and other nearby objects.
- Impeller cool mist humidifiers have a diffuser and a rotating disc. The rotating disc delivers water into the diffuser which then breaks it into droplets that float in the air. Like the ultrasonic humidifiers, they also release dissolved minerals and microorganisms from the water which can settle as white dust on household items.
Is white dust from humidifiers harmful?
In most cases, white dust from humidifiers is not harmful. However, the EPA advises the use of low mineral content water to reduce exposure to these minerals in dust form. If you have respiratory conditions like allergies or asthma, the white dust from humidifiers may exacerbate your condition.
Ultimately the Federal government has not concluded that the minerals dispersed by humidifiers pose a health risk, so it is best to err on the side of caution and use distilled water.
For your household items, there are no specific damages related to the white dust.
You can clean off white dust like any other dust without any special treatment.
How to prevent the release of white dust from your humidifier
Remember the white dust is released as a byproduct of the minerals through the mist and scattered across your room and furniture, but you may also notice this dust on the ceiling of your home!
Several simple routine maintenance steps can help you prevent the release of white dust from your humidifier.
Empty the humidifier tank or reservoir every day
Immediately after using your humidifier, turn it off and discard the residual water. I
f you have a high mineral content in your water, don’t let it sit in your humidifier for more than 24 hours or overnight. Unscrew the tank, pour out all the water, and if possible, leave to dry.
Once you’re ready to use it again, you can fill it with a new batch of water.
If you use your humidifier 24/7, ensure that you have a strict water changing routine that you follow. Also, if your humidifier has more than one tank, empty all the tanks at the same time and refill them.
Use distilled water only for your humidifier
If you can afford bottled distilled water or demineralized water for your humidifier tank, then hat’s better than tap water. The lower the mineral content in your water, the easier you can avoid mineral deposits and the release of white dust from your humidifier.
Keep humidity levels to between 40 and 50%
The humidity level also contributes to white dust in your home. Use a humidity meter to monitor the level, and switch off your humidifier if the humidity level exceeds 50%.
The higher the humidity level, the higher the chances of white dust clouding your furniture and other home appliances.
Change the filter in your humidifier
If your humidifier has a filter, it could be a contributor to white dust. Sometimes, the white dust formation may be because the demineralization filter in the humidifier needs replacing.
So, depending on how frequently your humidifier runs in a day, you should change your filter accordingly. Check your manual to confirm the location of the humidifier filter and the maintenance procedure for it.
Clean your humidifier regularly
Routine maintenance of your humidifier will prevent mineral build-up. Wash the humidifier with only water and mild soap if there are no deposits in the tank, or with distilled vinegar if you notice mineral deposits.
Store the humidifier properly when not in use
Do not store your humidifier with water inside it or while it’s wet. Change all used filters and cartridges before storage or before reuse. Always clean every part of the humidifier before use after storage.
Upgrade your appliance
If you have had your humidifier for awhile, difficult mineral deposits may have accumulated over time. The accumulation can increase the chances of your humidifier dispersing white dust.
Things to note in managing white stuff in a humidifier
- Always make sure that your humidifier is unplugged from the power source to avoid electrical accidents when cleaning
- If you or any member of your home has respiratory conditions, always use distilled water in your humidifier. Hard water causes white dust and microorganisms to release which can harm the lungs and worsen existing lung conditions.
- Evaporative humidifiers, cool mist humidifiers, and warm mist humidifiers are known to not emit white dust. If the dust is a big concern for you, consider switching to any of these models.
- Clean up white dust on your household items as soon as you notice them. Prolonged exposure to white dust could cause lung irritation.
