CPAP Maintenance

CPAP Water: Distilled vs. Tap (Which Is Better and Why?)

What kind of CPAP water should you use with your humidifierUnfortunately, there’s some confusion on this topic. Do you have to use distilled water? What happens when you use tap water?

In this post, you’ll learn what to look for and what to avoid. You’ll even discover an easy way to create an endless supply of clean water for your CPAP whether you’re at home or on the go.

Let’s dive in!

Different Types of Water for Heated Humidifiers 

The great debate: what kind of water is best for your heated humidifier! While many manufacturers recommend solely using distilled water, is that really the only option? In this section, we’ll dive into five different types of water and the effect they have on your CPAP humidifier and machine. 

The Truth About Distilled Water

Using distilled water with your heated humidifier is highly recommended by manufacturers, such as Resmed, to avoid mineral buildup and maximize the water chamber’s life. Over time, this buildup can prevent the humidifier’s heating plate from properly warming the water and providing enough moisture to soothe your nasal passage. 

Distilled water is created during the distillation process, as regular water is turned into a gas and then condensed back into a liquid, removing virtually all inorganic compounds and microorganisms, including: 

  • Calcium
  • Magnesium
  • Potassium
  • Phosphorous
  • Heavy metals
  • Bacteria

After this process is complete, only pure H20 is left behind. This is what makes distilled water an excellent choice anywhere a sterile environment is needed, such as in a medical clinic, laboratory, or your CPAP!

Before you reach for the faucet and fill your CPAP with tap water, consider using mineral-free water, such as distilled water. Doing so will extend the life of your machine and improve the quality of your sleep apnea therapy. You’ll wake up with less congestion and get the deep sleep you desperately need! 

The Truth About Using Tap Water in Your Humidifier

You may have read online from other CPAP users that tap water is safe to use. Unfortunately, this is not the best advice for you or your machine.

While tap water may seem like an easy and inexpensive way to fill your CPAP, the truth is, it often contains minerals and other unwanted contaminants, which can cause problems for your humidifier’s water chamber, tubing, and other machine parts.

The number of contaminants can vary depending on what region of the world you live in. According to a 2018 Nature study, around 10% of the water wells tested in California’s Central Valley were found to have dangerous arsenic levels.

While you may or may not be concerned about long-term exposure to chemical contaminants found in tap water, the immediate concern when using tap water with your CPAP is mineral deposits. 

As a best practice, avoid using tap water with your CPAP as it will leave behind hard calcified deposits when it evaporates from the humidifier water chamber. Over time, this buildup can feed fungal growth and affect your CPAP tubing, which can shorten the replacement schedule for your CPAP equipment. In some cases, not using distilled water may void the manufacturer’s warranty.

But what if you use tap water in your humidifier for one night?

Don’t worry; it’s not the end of the world if you use tap water every once in a while. However, be sure to give your humidifier chamber a good cleaning the next morning to ensure you remove any mineral deposits. 

If your only option is to use unfiltered tap water for the duration of your sleep apnea therapy, you may consider switching machines. Some heated humidifiers are designed to work with tap water, such as the Philips Respironics DreamStation Go. It’s one of the most advanced units on the market and is worth checking out.

The Truth About Purified and Filtered Water

Water that is filtered with a water filter, such as a Brita water pitcher, can be used with your CPAP and heated humidifier. This type of water filter can remove some impurities, but it should not be confused with purified water created from distillation, deionization, or reverse osmosis.

With that said, Reverse Osmosis(RO) Water can be used in your CPAP system. As long as you properly maintain and change the filters in your RO system, it is safe to use.

The Truth About Bottled Water and Alkaline water

If your bottled water is labeled Spring Water or Mineral Water, there’s a good chance it contains trace amounts of minerals and salts. You should avoid this type of bottled water for your CPAP humidifier. Some brands, such as Aquafina, purify the water to remove impurities and can be used if you don’t have access to distilled water. 

To find out exactly what’s in your specific bottled water brand, consumer reports created a list of water quality reports for more than 120 brands.

Unlike some bottled water brands, alkaline water is the opposite of distilled water and should not be used in CPAP machines. Alkaline water is filtered to increase the pH level making it less acidic. It may also contain other compounds such as silica and bicarbonate. 

A good example of alkaline water is the Smart Water brand, which includes electrolytes such as potassium, calcium, and magnesium. This is great for drinking but not ideal for CPAP therapy.

The Truth About Well Water

Using water from a well in your CPAP machine and humidifier is strongly discouraged. Reports of lung disease have been connected to using contaminated well water in a CPAP, and you also run a slight risk of ingesting harmful parasites

Do I Have to Use Water in My CPAP?

You don’t have to use water in your CPAP unless you use a humidifier. Most CPAP machines on the market today include a heated CPAP humidifier or allow you to attach one easily. If you choose not to use this comfort feature, you can use your CPAP device without water by turning the humidifier setting off.

What to Avoid: Don’t Add These to Your CPAP Water

Can you add anything to CPAP water? The list of substances you should add to your CPAP humidifier is slim: distilled water, that’s about it. 

Remember, your lungs are exposed to any substance added to your humidifier chamber. You should avoid using harmful solvents with your CPAP humidifier, such as:

  • Perfumes
  • Bleach
  • Alcohol
  • Ammonia
  • Antibacterial and glycerin-based soaps

What about essential oils? 

While you should never place essential oils directly in the humidifier, you can use products designed specifically for CPAP aromatherapy to get the same benefit. This can be an excellent addition to your therapy to relieve congestion and aid in relaxation.

How to Make Your Own Distilled Water for CPAP

You can easily make your own distilled water for CPAP at home. We’ve provided two different methods for you to try. The first method is super convenient and only requires a specialized pitcher and filter. 

The second method requires a lot of your time but can be a fun science experiment for you or the whole family! Whichever method you choose to use, you’ll always have a supply of CPAP water ready to use.

Method 1: Water Filtering System

This is the perfect solution to create an endless supply of distilled water for your CPAP. Pour some tap water into the pitcher, and just like magic, you’ve got CPAP water!h2o 4 cpap ion distilled water filtering system

Step 1: Pick up your H2O 4 CPAP Ion Distilled Water Filtering System.

Step 2: Fill the pitcher with water to create an endless supply of ion distilled water. 

It’s really that easy. This filtering system was made specifically for CPAP use. Use it to fill recycled water bottles and store them at home or create travel-size water bottles to use when you’re on the go. The pitcher comes with the correct filter pre-installed, which will last about two months and replacement filters are available from our store.

Method 2: DIY Distilled Water

This method only requires a few standard pieces of cookware and a stovetop. 

Before we begin, it’s important to understand that boiled water for CPAP is not the same as distilled water. Boiling water kills microbes but does not remove minerals or chemical contaminants. You may actually get more mineral buildup in your CPAP because the minerals become slightly more concentrated as the water evaporates when it’s boiled. 

Instead, we’ll be boiling water in a large cooking pot and capturing the water vapor into a smaller pot. The vapor is what we are looking to extract, not the boiled water.

For this method, we’re going to make about 1 ¼ cup of distilled water, which should take approximately 45 minutes of distilling time. This is a great option for saving money, but it can take a long time since you’ll need about 13 hours of distilling time to make one gallon! 

You’ll need the following:

  • Stove
  • One large cooking pot with a lid
  • A smaller cooking pot 
  • Ice cubes 
  • 8 cups of tap water
  • Oven mitts 

Step 1: Place a large pot on the stovetop and add 8 cups of water. Place a smaller pot inside of the large pot. The small pot should float above the water and have enough space around the sides and top between the large pot to encourage airflow. This will help circulate the water vapor as the water begins to heat.

Step 2: Set the stove burner to medium-high heat or approximately 190 degrees Fahrenheit. You may need to experiment with the temperature setting. A higher temperature will not create a higher yield. You should avoid boiling the water and instead focus on maintaining a nice simmer to make handling of the cookware easier. 

Step 3: Place a lid on the large pot upside-down. Flipping the lid upside down should allow for the condensed distilled water to drip into the smaller pot inside. Once you’ve done this, add ice cubes to the top of the large pot lid as this will create a difference in temperature and speed up the distillation process. You may need to replace the ice cubes as they melt, so take your oven mitts and carefully remove the lid from the large pot to discard the water that melted from the ice cubes. Use caution here as the lid will be hot!

Step 4: Avoid boiling off all of the water inside of the large pot, as this may damage your cookware. After about one hour, you should now have distilled water left over in the small pot. That’s it! Let it cool down before using, and now you have distilled water ready to be used in your CPAP!

Where to Buy Distilled Water for CPAP

Depending on where you live, sometimes you can find distilled water at the grocery store or your local pharmacy, but It’s usually sold in large, bulky one-gallon jugs. You can save time and avoid a trip to the store by browsing our distilled water selection formulated specifically for use with any CPAP humidifier. They’re the perfect size for easy storage or to pack with you for your next travel adventure.


Shop CPAP.com’s Distilled Water:


Tips for Traveling With CPAP and Distilled Water

Traveling with your CPAP? Whether you’re planning a road trip or flying to see your loved ones, here are some quick tips to ensure you never run out of CPAP water and get the best sleep possible while you’re away from home. 

Tip #1 Know how much water your CPAP will use: The amount of water you’ll need each night depends on several factors, including: 

  • Your room’s temperature and humidity level (is your destination a dry or wet climate?).
  • Your respiration rate (how fast you breathe).
  • The humidity setting you require on the CPAP machine (varies from person to person). 

If you’re traveling to a dry climate with low humidity, your machine will require more water. Conversely, if you are traveling somewhere such as the tropics, where humidity is high, you may not need as much water. According to Resmed, on average, a full chamber of water should last 1-2 nights. 

Tip #2 Prepare distilled water in advance: Decide how many nights you’ll be away from home. Depending on the factors we’ve discussed, 500 mL or 16.9 ounces of distilled water should last you about two nights. You may pick up a 6 pack of travel-size distilled water for CPAP or fill your own recycled water bottles using the water pitcher mentioned earlier.

Tip #3 TSA requirements for distilled water: If you plan on flying, you can bring 3.4 ounces of distilled water with your carry on bag and an unlimited amount of distilled water in a checked bag. Learn more about the TSA screening process by reading our complete guide to flying with a CPAP machine. 

Final Thoughts

Deciding what kind of water to use with your CPAP shouldn’t keep you from experiencing a comfortable night’s sleep. While there are many opinions on this topic, one thing is for sure: distilled water is the recommended choice among all CPAP manufacturers. While using tap water occasionally isn’t ideal, don’t let it stress you out if you need to use it in a pinch. 

Last but not least, if you ever need a re-supply of CPAP water or need to replace your humidifier chamber, we’re here to help. 

Now over to you! Did you find this article helpful? What kind of water do you use? Leave your comments below because we’d love to hear from you!

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