Can I Use Purified Water in My CPAP?

Key Takeaways

• Expert recommend only using distilled water in CPAP humidifiers, as it doesn't contain any minerals or impurities that can build up and damage the machine over time.
• If distilled water isn’t available, you can temporarily use purified bottled water or filtered tap water. Avoid putting untreated tap water in a CPAP humidifier.
• To prevent mineral buildup after using non-distilled water, make sure to thoroughly clean your CPAP humidifier chamber, tubing, and mask.

Why You Should Only Use Distilled Water

Distilled water is the safest and most effective option for your CPAP humidifier because it contains none of the minerals, chemicals, or microorganisms found in tap or filtered water. Using distilled water helps prevent mineral residue from forming inside the humidifier chamber, which can affect the machine’s performance and shorten its lifespan.

Distilled water is made by boiling water and capturing the pure steam as it condenses into a clean container. This process removes dissolved minerals, metals, and contaminants, as well as organisms like bacteria and fungi.

Because mineral deposits and microbial growth can interfere with effective therapy, manufacturers recommend using only distilled water for daily use. This helps keep your CPAP running properly, ensures better humidity control, and reduces the need for frequent deep cleaning or replacement of the water chamber.

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Using Non-Distilled Water in Your CPAP

While distilled water is the recommended choice for CPAP humidifiers, it isn’t always readily available. In some situations, alternatives like purified or filtered water may be used temporarily, but each comes with potential drawbacks, especially if used long term.

Can I Use Purified Water in My CPAP?

Purified water can be used in a CPAP machine if distilled water isn’t available, but it’s best viewed as a short-term substitute rather than a long-term solution. Purified water has been filtered to remove many impurities, chemicals, and microorganisms, making it safer than tap water for occasional use.

However, purified water may still contain small amounts of minerals, which can build up inside the humidifier chamber over time and reduce your device’s performance.

Can You Use Bottled Water in a CPAP Machine?

Some bottled water can be used in a CPAP machine, but it's important to look closely at the label. Not all bottled water is the same, and some types aren't recommended for CPAP humidifiers. The best option is to use bottled distilled water.

While the U.S. Food and Drug Administration's (FDA) regulations help make bottled water safe to drink, this doesn’t mean that all bottled water can be used in a CPAP. You should avoid mineral water, spring water, and any other bottled water with added minerals or flavors.

Can You Use Tap Water in a CPAP Machine?

Whenever possible, you should avoid using tap water in a CPAP machine. Tap water contains minerals that can collect in the machine. This mineral residue can impact the cleanliness and performance of your CPAP device.  

If your home uses well water or other untreated tap water, there may be health risks from putting tap water into your CPAP. Although uncommon, cases have been reported of respiratory illness arising from microbes in untreated water used in a CPAP humidifier. 

Although not recommended, you can use tap water in your humidifier if you have no other option. In this situation, it’s ideal to filter tap water first. While using tap water for one or two nights may not cause major mineral buildup, you should clean your CPAP more frequently when using tap water for any extended period. 

Can I Use CPAP Without Water?

Yes, you can use a CPAP machine without water in the humidifier, and the device will still deliver the pressurized air needed to treat sleep apnea. Many people choose to run their CPAP “dry” if they don’t experience dryness or irritation or when traveling without easy access to distilled water.

However, skipping the humidifier may lead to side effects like dry mouth or nasal passages or congestion, especially in dry climates or during winter.

How to Clean Your CPAP Water Tank

Keeping your CPAP water tank clean is essential for preventing mineral buildup, mold, and bacteria, all of which can affect your health and the performance of your machine. Most manufacturers recommend emptying the water chamber each morning, allowing it to air dry, and cleaning it regularly to keep it in good condition.

To clean your CPAP water tank:

1. Empty the tank and remove any remaining water after each use.
2. Wash the chamber with warm water and a mild, fragrance-free soap. Avoid harsh chemicals, which can damage the plastic.
3. Rinse thoroughly to ensure no soap residue remains.
4. Let it air dry completely on a clean towel before reassembling the humidifier.
5. Deep clean weekly by soaking the tank in a solution of one part white vinegar to three parts water for about 30 minutes, then rinsing well.

Note: Be sure to check your CPAP’s user manual, as some water chambers are dishwasher-safe (top rack only), while others should only be washed by hand. If the tank becomes cloudy, cracked, or difficult to clean, it may be time for a replacement to ensure safe and effective humidification.

Tips for Keeping Your CPAP Clean

In general, you don't need to use distilled water to clean your CPAP machine. However, you should use a mild soap or, in some cases, a mixture of water and distilled white vinegar.

For cleaning instructions specific to your device, look in the user manual or check with the manufacturer. Absent other guidance, you can wash CPAP parts with water and a gentle soap. 

On a daily basis, you should empty the humidifier chamber and wipe down your mask cushion. Every week, you should thoroughly clean your mask, headgear, and tubing. If your device uses a removable filter, clean it weekly. 

Some CPAP supplies need to be replaced on a regular schedule. These include a disposable filter, masks, mask cushions, headgear, and tubing. Check the user manual for a recommended schedule for replacing parts. At any point, you should replace these items if they become damaged or stained.

Traveling With CPAP Distilled Water

Traveling with your CPAP machine often raises the question of how to manage distilled water on the go. While bringing distilled water from home is ideal, it’s not always practical, especially when flying.

TSA allows travelers to carry 3.4 ounces distilled water for medical devices like CPAP machines, though you must declare it at security. You may also want to consider packing distilled water in your checked luggage.

If carrying your own water isn’t convenient, you can usually purchase distilled water at grocery stores, pharmacies, or convenience stores once you arrive at your destination.

When distilled water isn’t accessible during travel, using purified or bottled water for a short period is generally acceptable—just switch back to distilled as soon as possible to prevent mineral buildup in your humidifier chamber.

How to Make Distilled Water for CPAP

If you can’t get distilled water from a store, you can make a small batch at home using basic kitchen equipment. While it's not as convenient as store-bought, it can be a safe option for short-term CPAP use when done correctly.

1. Fill a large pot halfway with tap water and place a heat-safe glass or metal bowl inside so it floats without touching the bottom. This bowl will catch the distilled water.
2. Place the pot lid on upside down so the handle hangs down over the bowl. As steam rises and hits the cool lid, it will condense and drip into the bowl.
3. Heat the pot until the water gently boils, then reduce to a simmer.
4. Add ice to the top of the inverted lid to speed up condensation and improve efficiency.
5. Simmer for 30 to 45 minutes, checking occasionally to ensure the bowl hasn’t overflowed.
6. Carefully remove the bowl and let the distilled water cool completely before transferring it to a clean, airtight container.

Homemade distilled water should be used relatively soon and stored in a sanitized, sealed container to avoid contamination. While this method works in a pinch, regularly purchasing distilled water is still the most reliable and convenient option for long-term CPAP use.