Asked on Nov 10, 2017

How to clea orange mildew/mold from inside Humidifier water reservoir?

by Christine

Water reservoir has orange mold/mildew on inside of water reservoir of my humidifier, on the top, only opening on the reservoir is a small hole to fill the water. no way to get a hand or brush inside to scrub, I have tried soaking it in simple green, but mold not going away! My fault, I did not clean & empty properly, after last winter's use! 🙄 any ideas to clean my humidifier, would be appreciated!

  8 answers
  • Linda Sikut Linda Sikut on Nov 10, 2017

    This is for the basket, but it's the closest I could find from your question. I've never heard of orange mold, but you could give this a try. If it's actually a mineral deposit, I'd suggest you try soaking it in strong vinegar/water mix - meaning more vinegar than water.

  • Jason T. Lee Jason T. Lee on Nov 10, 2017

    I suggest fill with a bleach water mix and allow it to soak overnight. Kills almost every thing

  • Nancy Turner Nancy Turner on Nov 10, 2017

    You could try one of those baby bottle washers that has a sponge on top to get inside. If it isn't long enough, strap it to a small dowel to make the handle longer. Wash it with good hot water and soap to try to get as much as possible. Use the bleach to try to get the color gone. Fill and soak with vinegar water or straight vinegar because of its excellent antibacterial and antifungal properties to kill all the mold spores that may be left. Let is soak as long as you want, as long as it is at least 20 minutes to a half hour to let it work. Empty it out and let it dry before you use it. Hopefully this will work for you!

  • GMD22270496 GMD22270496 on Nov 10, 2017

    I get this in my humidifier water reservoir during winter. It is some kind of orange slime and my hand doesn't fit through the hole, either. To remove it, I pour uncooked rice into the reservoir, then add some vinegar (one half cup) and water (one cup), put the cap on and shake like crazy back and forth and up and down. Removes the orange slime and the scale quickly. The hardest part of the deal is flushing every bit of rice out but its abrasive quality is what scrubs the slime off.

  • Lokie Lokie on Nov 10, 2017

    I have had great results using hot water and vinegar. Let it soak over night then rinse well.

  • Christine Christine on Nov 12, 2017

    thank you, I will give the vinegar / water mix a try! And if need too, try bleach also

  • Anne Anne on Apr 04, 2020

    I had similar problem with orange matter. I read your ideas - good ideas - then went to to look for a manual. Looked up the picture of the kind I had and they had a tab for the manual. For my humidifier, the V4600, there are 2 weekly cleaning methods plus the ‘End of Season Care.’ Pages 8 - 10 in the v4600 manual. The vinegar comments above were right on!

    I cut and paste the following:

    Weekly Care and Cleaning:

    Scale Removal Directions: (?that’s what it says)

    1. make sure unit is unplugged and power switch turned off
    2. Remove Water Tank and empty base of any water.
    3. Remove mist nozzle and water tank cap and set aside.
    4. Fill water tank from bottom and water tray area of base with 1 cup of distilled white vinegar.
    5. Place mist nozzle and tank cap in water tray area of base to soak.
    6. Soak for 15-20 minutes.
    7. Using a soft cloth, gently clean transducer area in base to remove mineral deposits.
    8. Rinse water tray area of base, water tank, tank cap and mist nozzle until the smell of solution is gone.

    Disinfectant method using bleach & water:

    1. Add 1 Teaspoon of bleach to 1 gallon (3.8L) water.
    2. Add 1⁄2 to 3⁄4 gallon (1.9-2.8L) of the water/bleach solution to water reservoir of the main housing and water tank.
    3. follow steps 5-8 above

    End-Of-Season Care And Storage

    Follow the CLEANING instructions, starting on page 8, (Weekly Care & Cleaning) when the humidifier will not be used for at least one week or more, or at the end of the season

    At the end of the season, remove any accessories used with the humidifier and allow to dry properly.

    Dry the humidifier completely before storing. DO NOT store with water inside the main housing water reservoir or water tank.

    Pack unit in original carton and store in a cool, dry location.

    Consumer Relations

    Call us toll-free at: 1-800-477-0457


    Or visit our website at:


    Please be sure to specify model number.

    There are pictures in the manual. I wasn’t able to cut and paste them. Hope this helps!


      Humidifier machine and CPAP machine are two different things two way different how to clean them . You never use bleach on CPAP machine . Only white vinagar with very hot water. Hydrogen peroxide is only when you use a brush to clean only the water tank for build up won't come off

      Most of the time vinagar will get it off you need to let it stand for 30 minutes


    I have this problem all the time with my daughter CPAP now . She has been on it since she was 18 months old she is four now. On and off I get orange color film on the humidifier. I wash my daughter CPAP regularly every week still I see it it's hard to get off my daughter has reamed air CPAP so the humidifier area can open up and you place the water in it . Everytime I have to use qtips to get the orange stuff out. It's build up of mold if you don't take it out your asthma and lungs will get worse and allergies.

    I use vinegar and water soak it for 30 minutes. Then I wash it with dawn soap and use boiling water to rinse it out

    Hydrogen peroxide with water only for humidifier basket let it soak to get rid of the mold . Wash you supplies twice a week until no mold shows up