What Kind Of Water Should You Put In A Humidifier? 


Got a humidifier but are you wondering if you can just put any type of water in there or if there are any requirements for the water. It actually does matter and here’s what you should know. 

It’s best to use distilled water in a humidifier. This has the least potential health risks that using other types of water potentially has in a humidifier. Purified water from a good filtration system is OK to use in a pinch but can cause deposits in the humidifier. Avoid using tap water.

Why is distilled water the best option and what are the problems of using other types of water? You can find out and more below. 

What’s The Best Water For a Humidifier?

The best type of water to use in any humidifier is distilled water. Distilled water can be bought easily and cheaply at any pharmacy and some supermarkets. Its isn’t expensive. Sure, it still costs more than tap water but it’s much safer to use than other types of water. 

Distilled water that has been boiled and the vapor has been caught again. So it’s not simply boiled water. That means distilled water is pure H2o. Pretty much all other water has some inorganic material in it like metals and minerals. On top of that, tap water can have organic materials in it like bacteria. There can also be chemicals left in water even after it’s been purified. Filtration doesn’t filter everything but distillation does get rid of everything. 

Why is distilled water the best option to use in a humidifier? Humidifiers turn water into steam. However, there are many residues that don’t go out with the steam. That means they build up in the humidifier and cause deposits. This can clog up the humidifier and make it less efficient or even prevent it from working. 

Some humidifiers work in different ways and don’t use heat to make steam but might use an impeller or ultrasonic waves to create the droplets. In that case, the chance for deposits inside the humidifier is smaller but then you have those residues in the droplets. That means you can breathe them in which is usually not a problem but if there is something bad in the water, you can then get it in your body. 

Downsides Of Not Using Distilled Water In Humidifier 

To drive the point home, let’s summarize what the downsides are of not using distilled water in a humidifier.

  • Creates mineral deposits in the humidifier. The minerals in water don’t evaporate into the water droplets and so they stay behind. That means they create mineral deposits in the humidifier which can impact the functioning. 
  • Potential for spreading bacteria and mold spores around. Water that’s not completely clean and pure can have some unwanted guests in it. When you drink this water, you’ll likely be completely fine because your stomach acid takes care of most of these. However, when it’s breathed in, there is a higher chance for reactions like burning eyes, allergic reactions, etc. 
  • Contaminated water can contaminate the humidifier. Once you put water with some bacteria and/or mold in the humidifier, it can stay in the reservoir. That environment is perfect for them to grow further. Then when you fill the reservoir again, those bacteria are still there and will potentially be spread around. You’ll have to clean the reservoir first before filling it again. This just gets tedious. 

So using distilled water is best for both the humidifier and your health. 

Can You Use Purified Water In A Humidifier?

So what about purified water? The differences between purified water and distilled water might not be completely clear so here’s a quick rundown; 

Purified water is filtered. Distilled water is caught water vapor. Purified water is filtered through reverse osmosis, ion exchange or sand filtration. So that can still result in many different levels of impurities depending on filtration quality. However, to be called ‘purified’ it has to have very low levels of impurities. (Below 10 parts per million). 

In that regard purified water is very similar to distilled water. However, purified water still has essential minerals in it. This makes it good for drinking (you need the minerals in your body) but  not the best for a humidifier since it still has the downside of potentially creating deposits in the humidifier. 

If distilled water isn’t available, purified water is an option to use in a pinch but it’s not a great idea to use it regularly. If it’s properly purified, there will be no dangerous chemicals or other organic materials and organisms. So in that regard, it’s not an issue for your health. However, as said above, the deposits the minerals can leave behind are still a problem for you humidifier. 

Water that is not purified according to official standards (tested) but comes from a home filter can be OK to use but since it isn’t tested you can’t be 100% sure. It really depends on the quality and condition of the used filter if that’s safe. 

If you use purified water instead of distilled water, make sure to clean the humidifier regularly to prevent deposits from forming. 

Where To Get Distilled Water? 

Don’t have distilled water in your local supermarket? The best option is likely going to be the pharmacy. They will have distilled water. 

However, if you use your humidifier a lot or just a really big one like a whole house system, you probably want to buy in bulk and get it cheaper if possible. Amazon has some pretty good deals on distilled water. 

If you have a CPAP machine with humidifier and need water for that, there is special distilled water for this. These small bottles are perfect for one night and mean you don’t have to carry a big bottle to the bedroom. Get them here on Amazon. They’re surprisingly affordable compared to big jugs. Of course you can use this water for other types of humidifiers as well. 

In case a big jug has your preference, happy belly 1-gallon jugs are the cheapest you will find. Find it here on Amazon.

Another option is to get your own water distillation machine for at home. You might think they would be very expensive but they are actually pretty affordable. A small water distiller can usually make up to 1/4 a gallon of distilled water a day. This is plenty to run a humidifier and more. You can find a cheap one here on Amazon.

Of course a distiller costs more than a jug of distilled water but you can use it for a long time so if you use a humidifier every day for a long time, this could be worth the investment. It also means you’re not dependent on getting your water delivered on time. 

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