How to Clean a Humidifier Filter


Robert asked: How do I clean a humidifier filter. My humidifier filter has a bunch of lime build up. Is there a home remedy to clean this filter? It looks like it is made out of some kind of paper.

Filters are constructed out of a variety of materials. If the filter is made of paper, you will need to dispose of it and purchase a new one. The paper will be ruined in the cleaning process. If the filter is made of a plastic or other water-resistant material, you can clean it and remove the lime with the method below.

You Will Need:

  • Vinegar
  • Bleach
  • Bucket
  • Rubber gloves (optional)
  • Towels
  • Bucket
  • Soft cloth

Steps to Clean the Filter:

  1. Unplug the humidifier.
  2. Remove the tank. These generally sit on top of the filter.
  3. Set the tank on a towel, in a tub or in the sink. Sometimes they continue to drip water.
  4. Carefully lift out the filter.
  5. Place it in the sink or tub. If neither of these are available, place it in a bucket filled with cool water.
  6. As you are rinsing, look for any damaged or moldy areas. Mold may be green, pink or black. Mineral deposits may also be present.
  7. If there is mold present, fill the sink or bucket with one part bleach and six parts water.
  8. Place the filter in the water mixture and allow it to soak for 10 minutes.
  9. Remove the filter from the water and rinse it completely with cool water.
  10. If mineral deposits are present, fill the sink or bucket with one part vinegar and two parts water.
  11. Soak the filter in the vinegar and water for 20 minutes.
  12. Rinse completely with cool water.
  13. Use a soft cloth to wipe out the basin where the filter sits. Use the bleach or vinegar to treat any problem areas found there.
  14. Place the filter back into the holder while it is still damp.
  15. Fill the tank and return it to the top of the filter.
  16. Run the humidifier as normal.

Additional Tips and Advice

  • If your filter is not made of plastic or cannot withstand chemicals, skip the vinegar and bleach soakings. Simply rinse and soak the filter in clean water to clean it.
  • Check your owner’s manual for cleaning guidelines and suggestions. If it differs from the instructions here, follow those provided by the manufacturer or your specific model.
  • To avoid lime build up in the future (and keep away bacteria and fungi), fill the humidifier with distilled or demineralized water. Regular tap water contains minerals that leave a build-up which can feed bacteria growth.
  • Many filters are designed to be tossed and replaced. If yours has passed its prime, don’t hesitate to purchase a new one.
  • To sanitize the inside of your humidifier, wipe it down with hydrogen peroxide (3%). Allow it to air dry completely before use.


  1. Josh says:

    Thank you so much! I have a humidifier and no longer am able to buy the filters. Amazon sells them, but they are more than twice of what I paid for the humidifier; so thank you very much.

  2. John H. says:

    I’m glad you were their with the good advice. I had been just washing with fresh water and now since I followed your directions the humidifier works much better and fills the room with moisture once again. Thanks, John H.

  3. Anon. says:

    It’s dangerous to clean with bleach then with vinegar; it creates a toxic fume that causes damage to the mouth, throat and esophagus. I would choose one or the other, preferably vinegar since bleach is really, really, really bad for you, but NEVER both.

  4. Jim says:

    Anon., re: bleach & vinegar

    Don’t go scare-mongering with the bleach & vinegar issue. Yes, mixing *undiluted* bleach and vinegar is bad chemistry, BUT:

    #1. Read the instructions. It clearly says “Remove the filter from the water [and bleach MIX] and RINSE IT COMPLETELY with cool water.”

    #2. This is a dilute bleach solution, as is the vinegar SOLUTION. As *weak solutions*, even if they were mixed together, they’d not likely produce much of a reaction.

    That said, more emphasis on the rinsing would be appropriate.

  5. Marvin says:

    You can clean paper filters too. One gallon of water and 1/2 cup of white vinegar, and soak for 12-24 hours. Rinse and let dry. I have two paper filters that I alternate and so far have done this half a dozen times and the paper filters are still holding up.

Leave a Comment