How to Clean a Portable Humidifier

White portable humidifier releasing steam next to plant

The Spruce / Sarah Lee

Project Overview
  • Total Time: 45 mins
  • Skill Level: Beginner
  • Estimated Cost: $5 or less

Dry air can make a space much less comfortable and even lead to some health and cosmetic issues. One standard method of combating dry air is to use a home humidifier, which puts much-needed moisture back into the air. However, sometimes a dirty humidifier can do more harm than good. The secret to getting positive results from your humidifier is to keep it clean. Here's how:

Why You Don't Want a Dirty Humidifier

Any issues caused by a humidifier almost always occur because the machine contains bacteria or mold. It's easy to understand how this can happen. The purpose of a humidifier is to hold standing water, evaporate it through a system of damp wicks, and blow out that moistened air.

That's all well and good if the water being evaporated is sterile, but the water reservoir is just the kind of damp environment that promotes mold and bacteria growth. And once your humidifier gets dirty, your appliance has become a distribution system for the bacteria and/or mold inside it. As mold spores are blown into the air, they hunt for new moist, warm places to take up residence—often in humans and pets living in the space.

How Often to Clean a Humidifier

Fortunately, it's fairly easy to prevent your humidifier from becoming a petri dish. Just clean it regularly. If you use a humidifier daily, a cleaning routine repeated every three days should keep your air appropriately moistened and clean.

Brown bottle of hydrogen peroxide, glass container of distilled white vinegar and a toothbrush to clean portable humidifier

The Spruce / Sarah Lee

What You'll Need

Equipment / Tools

  • Clean toothbrush


  • Hydrogen peroxide or white distilled vinegar
  • New humidifier wick (if needed)


  1. Clean the Base

    To deep clean your machine, begin by disinfecting its base using three percent hydrogen peroxide or white distilled vinegar. Start by unplugging the humidifier unit from the wall outlet, then remove the unit's water tank and filter.

    Pour a generous amount of hydrogen peroxide or white distilled vinegar into the base of the humidifier. Use a clean toothbrush to scrub away film and mineral build-up from the base of the unit.

    Allow the liquid to sit in the humidifier’s base for at least 10 to 30 minutes, then pour the liquid out. Rinse by adding and swishing fresh water to the base. If any mineral residue is left, repeat the entire process. When the base is clean, let it air dry.

    Base of portable humidifier scrubbed by toothbrush to remove film and mineral build up

    The Spruce / Sarah Lee

  2. Clean the Wick

    Ultrasonic humidifiers don't have an evaporative wick, but many evaporative humidifiers have a wick pad that soaks up water to facilitate its evaporation. This wick can either be a flat pad or a cylindrical pad that fits around a rotating drum.

    Whatever type of wick you have, remove it from the humidifier each time you clean it and thoroughly rinse it in clear water. Don't use any cleaning solutions on the wick. If the wick has become caked with white mineral deposits, replace it with a fresh wick pad.

    Humidifier wick pad rinsed under running water in sink

    The Spruce / Sarah Lee

  3. Clean the Tank

    A humidifier's water tank is also a haven for bacteria and mold. Mix a solution of four parts water to one part hydrogen peroxide (3 percent) in the tank. Allow the solution to remain in the tank for at least 30 minutes. Empty the solution, then rinse thoroughly with clean water and let the tank air dry.

    Hydrogen peroxide and water mixture poured into humidifier tank for cleaning
    The Spruce / Sarah Lee

Is Your Humidifier Still Dirty?

If your humidifier is still grimy even though you are cleaning it thoroughly and regularly, it's time to stop using tap water and switch to distilled water. Tap water can contain minerals and contaminants that encourage bacteria growth. These minerals are especially prevalent if you have hard water; it's these minerals that cause the white dust that's left behind in the tank and on the evaporative wick after the water evaporates away.

Distilled water is produced by an evaporation process that captures only the water molecules and leaves behind the mineral deposits. Combined with regular cleaning of the humidifier, tank, and evaporative wick, using distilled water should help keep the appliance clean.

Consider a New Humidifier

Over time, there can be such a build-up of mineral deposits that a portable humidifier can no longer work efficiently. When this happens, it's time to buy a new humidifier. Where there is a noticeable build-up of mineral deposits, a build-up of bacteria is almost certainly present as well.

Now is the time to switch to an antimicrobial humidifier. These units are able to purify stored water, so they produce a cleaner and healthier mist. To keep your machine in tip-top-shape, follow instructions for cleaning.


If your main forced-air HVAC system has a built-in humidifier feature, its components need to be cleaned and maintained regularly, just as with a portable humidifier. Consult the instructions for your furnace/air conditioner system for directions on how to clean and maintain a whole-house humidifier unit.

Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Mold. Centers for Disease Control and Prevention.

  2. Mold. Centers for Disease Control and Prevention.

  3. Questions Abound on the Safety of Humidifiers. McGill University.