How to Clean a Humidifier: Step-by-Step Guide With Vinegar

To clean a humidifier, unplug it, empty the water, soak the tank and base in white vinegar for 15 to 20 minutes, scrub off the scale with a soft brush, rinse well, and let every part dry. Do a quick clean and water change every day, and a deeper clean about every third day, as the EPA advises.

A humidifier can help with dry skin, a stuffy nose, and dry winter air. But if it is dirty, it can also blow mold and bacteria into your room. This guide shows you how to clean yours, how to keep it clean, and how to deal with slime, white dust, and smells.

Why cleaning matters

A humidifier holds warm, still water. That is just what mold, germs, and mineral scale like. If the water sits for days, microorganisms grow in the tank and base. Then the humidifier puts them into the air as a mist.

The EPA explains that dirty humidifiers can release contaminants and minerals into the air. That is a bigger worry for people with asthma, allergies, or other breathing problems. Mayo Clinic also says a humidifier that is not cleaned properly can make symptoms worse, not better.

Signs it is time to clean it right now:

• Pink, orange, or green slime in the tank or base
• White crust around the heating plate or in the tank
• A musty or sour smell from the mist
• White dust on furniture near the humidifier
• Black specks that look like mold
• A film on the water surface

What you need

• Distilled white vinegar
• A soft brush or old toothbrush. A small bottle brush helps with narrow spots.
• Clean cloths or paper towels
• Dish soap for the tank
• 3% hydrogen peroxide (optional, for disinfecting)
• Distilled water for rinsing and refilling

You do not need harsh chemicals. White vinegar handles most jobs.

How to clean a humidifier with vinegar (7 steps)

These steps work for most cool mist and warm mist humidifiers. Check your manual first, since some brands give special instructions or warn against vinegar on certain parts.

1. Unplug the humidifier. Never clean it while it is plugged in.
2. Empty the tank and base. Pour out all the water and take apart every removable part, including the tank, base, lid, and any filter.
3. Fill the base with vinegar. Pour in enough white vinegar to cover the heating element or the bottom of the base. Fill the tank about one third full, put the cap on, and gently shake it so the vinegar coats the inside.
4. Let it soak for 15 to 20 minutes. For heavy scale, you can soak up to an hour.
5. Scrub away the buildup. Use a soft brush on the base, around the heating plate, and around any small openings. Do not use anything sharp on plastic parts.
6. Rinse well. Rinse every part with clean water until you cannot smell vinegar. If you want, finish with distilled water.
7. Dry everything. Wipe the tank and base with a clean cloth and let all parts air dry completely before you put it back together.

How to disinfect a humidifier

Cleaning removes scale. Disinfecting helps kill germs. The EPA suggests that after cleaning you can disinfect with 3% hydrogen peroxide or a diluted bleach solution, and then rinse thoroughly. Follow your humidifier maker's directions, since some products warn against bleach.

A common way to do it:

1. After the vinegar clean and rinse, pour 3% hydrogen peroxide into the tank and base.
2. Let it sit for about 20 minutes.
3. Pour it out and rinse everything several times with clean water.
4. Let the parts dry.

If you use bleach, the EPA suggests about 1 tablespoon of household bleach per gallon of water. Let it sit for about 5 minutes, then rinse well until you cannot smell bleach.

How often should you clean it?

Follow this simple schedule, based on EPA guidance for portable humidifiers:

It sounds like a lot. But a quick rinse takes only a minute, and it prevents most of the slime and smell.

What water should you use?

Use distilled water if you can. Tap water has minerals like calcium and magnesium. When a humidifier makes mist from tap water, those minerals can end up:

• As scale inside the humidifier
• As white dust on furniture and floors
• In the air you breathe as tiny particles

The EPA says to use water with low mineral content, such as distilled water, and notes that distilled water is a better choice than most tap water. A gallon of distilled water costs only a few dollars. If you use tap water, you will need to clean the unit more often. Some filter or demineralization cartridges also help, so follow the maker's advice.

How to fix common problems

Pink or orange slime

This is usually bacteria growing in the water. Throw out the water, then clean and disinfect the whole unit. Rinse it well. If the slime keeps coming back quickly, change the water more often and use distilled water.

White dust on furniture

This comes from minerals in tap water. Switch to distilled water. Ultrasonic humidifiers are known for making white dust, because they send the minerals out with the mist.

Musty smell

A musty or sour smell means mold or bacteria. Clean and disinfect, and replace the filter if there is one. If the smell comes from the room and not the humidifier, see what causes a musty room smell.

Hard scale on the heating plate

Fill the base with vinegar to cover the plate, soak for 30 minutes or longer, then scrub gently. Repeat if needed.

Water leaking from the base

A cracked tank or a worn gasket can cause leaks. Check that the cap is tight and the tank is seated right. If it still leaks, replace the tank or the unit.

No mist or weak mist

The cause may be scale, a clogged filter, or low water. Clean the unit. If you have an evaporative model, replace the wick filter.

How much humidity do you need?

More is not better. The EPA says to keep indoor relative humidity below 60 percent and ideally between 30 and 50 percent. Too much moisture can cause mold, damp air, and dust mites to thrive.

You can check with a small humidity gauge, called a hygrometer, for about $10 to $15. If you see water on your windows, the air may be too humid. Read more in our guide on window condensation in winter.

In winter, lower humidity levels work better when it is very cold outside, because warm moist air hits cold glass and turns to water. If your home feels damp in the summer, a humidifier is not what you need. See why your house can feel humid even with the AC on.

Which type of humidifier is easiest to keep clean?

Warm mist models can make the water hot, so keep them away from kids and pets.

Storing your humidifier for the summer

At the end of the season:

1. Empty it and clean it with vinegar.
2. Disinfect it as above, then rinse.
3. Let every part dry completely. Damp parts can grow mold in storage.
4. Throw away the old filter.
5. Store it in a clean, dry place with the lid off, or wrap it in a clean cloth.

In fall, give it one more quick clean before you plug it back in. A humidifier that sat all summer may have dust or mold.

When to replace your humidifier

Think about getting a new one if:

• It still smells bad after a deep clean
• The tank is cracked or leaks
• Mineral scale will not come off
• It is more than 5 to 7 years old and has stopped working well
• Replacement parts are no longer made

Dust and your humidifier

A dry house tends to be dustier, and a humidifier can add to the dust problem if it releases white mineral dust. If you are fighting dust, check out why your house is so dusty.

The bottom line

Clean your humidifier every third day and change the water every day. Soak it in white vinegar for 15 to 20 minutes, scrub, rinse, and dry. Use distilled water to cut down on scale and white dust, keep humidity between 30 and 50 percent, and never mix vinegar with bleach. If it still smells bad after a deep clean, replace it.