Can You Use Purified Water in a CPAP Machine?

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Why You Should Use Distilled Water in a CPAP Machine

Distilled water is the best choice for CPAP humidifiers because it’s pure water that’s free of minerals and bacteria. Considered the purest form of bottled water, it’s produced by boiling water and then condensing the vapor back into liquid form.

Hospitals, labs, and factories often use distilled water instead of tap water because it prevents limescale buildup on devices. And using the wrong type of water in your CPAP humidifier can cause mineral buildup, scaling, or bacterial growth. It may also irritate your airways or cause your machine or its components to break down.

Can You Use Tap Water in a CPAP Machine?

While tap water is readily accessible and may be tempting to use in your CPAP humidifier, it can contain mineral deposits and other chemicals that may damage your machine or result in potentially harmful bacterial growth Trusted Source National Library of Medicine, Biotech Information The National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information. View Source .

Tap water can come from a well or a municipal water supply. Though your tap water may be perfectly fine to drink, it may contain minerals that can cause buildup or scaling in your CPAP machine. Tap water may also contain additives like chlorine or fluoride that can harm your machine.

While you can boil water to kill bacteria, it will still contain any mineral content that was there prior to boiling.

Can You Use Bottled Water in a CPAP Machine?

You can use bottled water in your CPAP humidifier if it’s distilled water. Most bottled water used for drinking is purified or spring water. These don’t contain bacteria, but they may have minerals like calcium and magnesium that can leave residue in your humidifier and may cause it to wear out quicker than expected. Bottled water may also include:

• Spring water: Generally rich in mineral content, spring water comes from aquifers and is naturally filtered underground before it reaches an above-ground spring. Artesian water is similar to spring water, but it comes from an artesian well that taps an aquifer. Spring water may be refreshing to drink, but when you run it through your humidifier, the minerals can cause the machine’s components to break down.
• Mineral water: Mineral water sold in the U.S. must come from an underground water source and needs to contain a minimum amount of total dissolved solids Trusted Source U.S. Food and Drug Administration (FDA) The FDA is responsible for protecting the public health by ensuring the safety, efficacy, and security of human and veterinary drugs, biological products, and medical devices; and by ensuring the safety of our nation's food supply, cosmetics, and products that emit radiation. View Source to be branded as such.

Can I Use CPAP Without Water?

You can use a CPAP machine without water, but it may be less comfortable for some people. The water in a CPAP humidifier is used to add moisture to the air you breathe, which can help reduce side effects like dry mouth, nasal congestion, and throat irritation. If you choose not to use water, your CPAP will still deliver pressurized air, but the airflow will be dry.

Some people temporarily use CPAP without water when distilled water isn’t available, such as while traveling or during a supply shortage. In these situations, many users turn off the humidifier feature or remove the water chamber entirely. Others may use a heat and moisture exchanger (HME), which captures moisture from exhaled air and helps humidify incoming air without the need for water.

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How to Clean Your CPAP Humidifier Chamber

Regularly cleaning your CPAP — including the water tank — helps prevent mineral buildup, bacteria growth, and unpleasant odors. Most manufacturers recommend cleaning the water chamber at least once a week, or more often if you notice residue or discoloration.
Trusted Source Annals of the American Thoracic Society View Source

To clean your CPAP humidifier chamber, follow these steps:

1. Start by unplugging your machine and removing the water chamber. Empty any remaining water.
2. Soak the tank in warm water and a mild, fragrance-free dish soap.
3. Gently scrub the inside with your hands or a soft brush, paying attention to corners where residue can collect.
4. Rinse the tank thoroughly with clean water to remove all soap.
5. Allow the water chamber to air dry completely on a clean surface before reinserting it into your CPAP machine.

Avoid using harsh chemicals, alcohol, bleach, or abrasive cleaners, as these can damage the tank and leave behind harmful residues. If mineral deposits develop, some manufacturers allow occasional soaking in a solution of water and white vinegar, followed by thorough rinsing. Trusted Source American Journal of Respiratory and Critical Care Medicine View Source Always check your CPAP machine’s manual for specific cleaning instructions to ensure you don’t void the warranty or damage the equipment.

Tips for Traveling With CPAP Distilled Water

Traveling with a CPAP machine can make accessing distilled water more challenging, but a little planning can help keep your therapy comfortable.

If you’re flying, consider purchasing distilled water at your destination rather than packing it, since liquids in carry-on luggage are restricted. TSA allows travelers to carry 3.4 ounces distilled water for medical devices like CPAP machines, though you must declare it at security.
Trusted Source U.S. Transportation Safety Administration View Source You may also want to consider packing distilled water in your checked luggage.

If distilled water isn’t available, you can temporarily use CPAP without humidification or turn off the humidifier until you’re able to find distilled water again. Heat and moisture exchangers (HMEs) can also be a convenient alternative, as they provide humidity without the need for water.

When traveling internationally or to remote locations, it may help to research availability ahead of time or plan for backup options. Always empty and dry your CPAP water tank before packing to prevent leaks and reduce the risk of bacterial growth during transit.

Best Place to Buy Distilled Water

Distilled water is easy to find. Most grocery stores, drug stores, and mini-markets carry distilled water. You can also buy it from online stores and CPAP suppliers. Some online retailers offer subscriptions so that you don’t have to worry about reordering or running out.

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