I have a small cool mist humidifier. It has a water tank and ejects a mist and does not have a filter or anything. It is "TaoTronics" brand in case anyone wants to find it.

I've noticed pink streaks accumulating where the mist ejects, and also where the water collects. This seems to be mold, and a lot of it.

I cleaned it thoroughly with water and vinegar and thought perhaps running it continuously would prevent mold from accumulating, but I was wrong. After a week of continuously running it 24/7, the mold returned.

How can I prevent mold from accumulating in this humidifier? The only options I see at this time are:

  1. Clean the humidifier weekly (huge hassle).
  2. Always run the humidifier with a mold-killing substance in the water (vinegar? chlorine? Would this be SAFE? Would it break humidifier?)
  3. Use distilled water (expensive and hassle).

How can I prevent this humidifier from getting moldy?

  • 1
    What you're seeing is likely not mold, but Serratia Marcescens bacteria. Still, it should be cleaned. We switched to using distilled water a few years ago. While it greatly reduces how often we need to clean the humidifier, we still need to clean it at least monthly.
    – Sam
    Commented Apr 3, 2019 at 13:03
  • I've seen cleaning balls at the store, but have no idea how/if they work. Something to look into tho...
    – JPhi1618
    Commented Apr 3, 2019 at 15:02
  • Regular cleaning and better water are your two best choices. Adding chlorine will degrade rubber seals more quickly. Adding vinegar modifies the acidity of the water and will likely contribute to early death, as well as smell while running.
    – Tyson
    Commented Apr 3, 2019 at 15:12
  • @Tyson This thing is cheap. I don't mind reducing its life if chlorine means I never need to wash the thing. Would this work?
    – Behacad
    Commented Apr 3, 2019 at 17:55
  • Anything you add to the water is sprayed into the air, and the tiny droplets can go deep into the lungs. Distilled water is safest, but you'll still need to clean often. Commented Apr 3, 2019 at 18:34

6 Answers 6


My mom puts a silver dollar in hers, I think they need to be pre 1960's to have enough silver she says the silver kills stuff naturally (she also puts one in the pitcher in the fridge for drinking water) she has done this for years and swears by it.

  • You could also just buy the 99% pure silver coins (Canadian silver maple leafs) which would ensure they are high enough in silver. I've also read of using a combination of silver and copper (both having excellent antimicrobial properties) so throwing in some pre 1982 pennies might also help.
    – tk421
    Commented Apr 4, 2019 at 0:13
  • I think but am not sure of all of the following: the type of silver that disinfects is ionic silver and also is not good for human health. Not sure if this stuff would get airborne in a humidifier. I suppose if you had an ultrasonic or an impeller humidifier, it would get airborne. I suppose a warm mist/vaporizer/boiling water type would not let the silver get airborne (like when distilling water, only low boiling temperature things get airborne). Not sure about a wick based / evaporative humidifier. Commented Dec 29, 2021 at 18:20
  • 1
    The World Health Organization has a paper on their website from the Centre for Research into Environment and Health.. whatever that is, called "Silver: water disinfection and toxicity" and another paper on their website called "Silver as a drinking-water disinfectant".. Someone read them and report back, haha. I wonder if silver remains active for long enough in water to be useful, and if it has any potential negative health effects. Commented Dec 29, 2021 at 18:27

You can just buy a humidifier treatment solution which also has algae/bacteria suppressing chemicals. Typically you add 1-2 capfuls per gallon of water. They were pretty standard with the older large humidifiers but also work for the newer cool mist humidifiers. Just search cool mist humidifier water treatment bacteriostatic and make sure the one you buy is safe for your humidifier.

  • The humidifier presumably is putting this substance in the air, and we can breath it in. Are these things safe? In fact I just looked at toms of these and they explicitly say not to be used in mist humidifiers.
    – Behacad
    Commented Apr 3, 2019 at 22:59

I think boiling the water would likely kill the bacteria and mould. Possibly doing this in conjunction with the other proposed answers should do the trick ever in the most extreme case. Silver has known antibacterial effects and a cap full of solution into boiled water doesn't sound too unreasonable. With a kettle it would be easy. Boil the water before bed and pour it in, in the morning.


I have read many articles that say that you should only use distilled water with a humidifier. The reason being is that there are numerous minerals in regular tap water that will become airborne with cool mist humidifiers. These minerals become "white dust". This white dust is a very fine particulate that takes a rather good air filter to take out of the air. Any fine particulate is potentially harmful for you to breathe in as it irreparably damages your lungs. Do yourself a favor first of all and use only distilled water. We also use a tiny amount of vinegar in our humidifier and it certainly makes the humidifier last longer in between cleanings. We still clean ours once a month at a minimum however.

  • 1
    Strange how you say use only distilled water because otherwise you will send dangerous compounds into the breathable air, and then you proceed to add vinegar to the water.
    – Behacad
    Commented Apr 4, 2019 at 11:33

I bought two ultrasonic vaporizers a few years ago and they drove me nuts, spewing minerals (hard water) and clogging up with slime, requiring weekly maintenance. They're gone now, replaced by evaporative units (fans and filters). The main downside is the cost of the filters. Otherwise they only need cleaning at end of season. Most of the gunk goes out with the used filters.

  • There is a possibility that it's cheaper, or at least easier to just keep buying new, cheap Vick's warm mist vaporizer humidifiers from time to time instead of buying new filters for an evaporative humidifier. Energy costs are a factor though. Commented Dec 30, 2021 at 18:15

TLDR: use a warm mist humidifier with RO or distilled water and just empty it out between uses so it can dry. Occasionally (idk, once per week or few weeks?) swish white vinegar around.

I use a warm mist humidifier because the cool mist vaporizers eject particulates into the air that aren't good to breathe in. The only other kind of humidifier that doesn't put particulates into the air is an evaporative / wick / filter based humidifier, but the filters are more expensive than just replacing a warm mist humidifier, and I still haven't had a problem with my warm mist humidifier a few months in. I use the Vick's v745 and v750. I forget why I decided to go with those after researching.

I read a couple of World Health Organization reports on silver as a disinfectant, and it was only effective for a few bacterias/fungi/viruses. I forget the exact details, but I just remember it wasn't promising. Also in some circumstances (I forget what exactly), silver can be toxic.

Just use RO water or distilled water or maybe even distilled RO water to prevent sediment from building up too quickly.

I had bought an aquarium UV light, but have found it unnecessary and impractical.

  • A link to said WHO reports would be most helpful.
    – FreeMan
    Commented May 6, 2022 at 13:09

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