Do I Have To Use Distilled Water With My CPAP Machine?

November 09, 2018

Do I Have To Use Distilled Water With My CPAP Machine?

A popular topic we often get asked about is water. Do I have to use distilled water with my CPAP device? What is distilled water?  Can I use tap water? What is the difference between tap water and distilled water? Do I have to use distilled water when I'm travelling? 

It is important to learn the difference between types of water available and what you should use with your CPAP machine. When it comes to using a CPAP humidifier, you need to be using the right cleaning techniques and tools to prolong the life of your CPAP equipment. That includes water type too.

CPAP manufacturer Resmed (who makes AirSense 10 and S9s) recommends filling your water tub with distilled water to maximize the tub's lifespan. Respironics (who makes DreamStation and Remstars) recommends using distilled water in your humidifier to avoid mineral deposit buildup.  

We recommend CPAP users to follow the manufacturer's user manual for the optimal performance of their products.


Types Of Water To Use With Your CPAP Device

First of all, it is good to know what the different types of water that you can use are. There are three main types that we recommend using with your CPAP equipment. These include: 


  • Distilled water
  • Springwater
  • Tap water


Distilled Water

Distilled water is water that has been boiled into vapour in one container and collected back into liquid form in a separate container. This distillation process filters impurities behind when the water evaporates. This removes microbes and minerals like calcium and magnesium. 

As we mentioned above, many CPAP manufacturers such as Resmed and Respironics recommend using distilled water for your CPAP machine for the very reason that it decreases the risks of your CPAP equipment becoming mineralized.



Springwater is water filtered naturally (by rocks) and contains minerals. As the name suggests, spring water is derived from an underground formation where water flows naturally to the earth’s surface. Similar to tap water, spring water isn’t necessarily filtered so it will contain microbes and minerals. 

We recommend that you only use spring water in your CPAP machine if your manufacturer has recommended that you do. 


Tap Water

Tap water is water containing solutes like chlorine and fluoride and also contains minerals. Unlike distilled water, tap water is not boiled in order to filter out any impurities. Generally, it is better compared to that of spring water. 

Depending on where you live can also impact the tap water that you use. For example, if you live in a city then you may notice that tap water has higher levels of fluoride than rural areas.

The difference between these three types of water would be the presence of minerals, microbes, organisms or chemicals. In most cases, distilled water is often the preferred option for your CPAP device due to the decreased presence of minerals and chemicals.


Tap Water & Your CPAP Device

As mentioned previously, if your CPAP manual says to use distilled water, stick with distilled water. Water in other forms can mineralize, harden, discolour and scale your water chamber with time.  

That being said, we have seen CPAP users use tap water - it decreases their product's lifespan and increases the frequency they need to replace their tubs. Make note of your water chamber's life span and replace as recommended by the user's guide. 


What Water To Use With Your CPAP Machine When Travelling 

A key consideration when travelling is the quality of water. If you don't trust the water supply, don't use the water in your CPAP machine. Find access to a drug store or a pharmacy where you can purchase distilled water. 

Using distilled water in these instances will minimize your exposure to any risks to both your health and your CPAP equipment. Some CPAP users temporarily use bottled water until they find distilled water.

Finally, if accessing safe water is an issue when on the road, consider forgoing the usage of your humidifier until you get back home.

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Sizing Guide For Select CPAP Masks

Select CPAP Masks have sizing guide to help you select a size. 

Click on the mask name below to view, print and measure with their size guide.

Other masks are packaged as fitpacks with all size cushions included and do not have size guides available. 

Nasal Masks

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Other helpful resources:

How To Select A CPAP Mask – Help Centre - All the help you need...instantly! (

What Size CPAP Mask Do I Buy? – Help Centre - All the help you need...instantly! (