The condition is often treated with a continuous positive airway pressure (CPAP) machine. This device works by delivering a flow of pressurized air through a mask to keep airways open.

CPAP machines often have heated humidifiers. The instructions typically say you should use distilled water in the humidifier.

This article discusses the benefits of a CPAP humidifier. It also looks at when and why you should use distilled water in your CPAP machine.

Benefits of a CPAP Humidifier

A heated humidifier can make your CPAP machine much more comfortable. It can reduce dry mouth and congestion.

Outside factors may impact how often you use your humidifier. Local climate and personal preference may all play a role. Depending on your manufacturer, you may be able to change the temperature and humidity levels.

Infections Nasal congestion Inflammation Nosebleeds

If you’re using standard tubing, condensation within the tubes may cause problems. This is sometimes called “rainout.” It is more of a problem when your bedroom is cool.

ClimateLine heated tubing can help prevent this problem when you turn up the humidity.

When possible, avoid letting the humidifier run dry. This can cause the motor to overheat. Refilling the water reservoir every night can prevent this.

Can You Use Tap Water With a CPAP Humidfier?

The safety of your CPAP machine depends on the quality of the water you use. Tap water may contain microbes, minerals, and chemical contaminants.

You can kill microbes by boiling water. Boiling does not remove minerals or chemical contaminants, though.

Minerals like calcium, magnesium, and iron are what make your water “hard.” If they are in the water you use in your humidifier, they will cause a build-up of mineral deposits, called scale. This could damage the machine.

Filtering can remove some of the minerals. It may not remove microbes or other chemicals, though. Bottled, distilled water is the safest option.

Distilled water prevents mineral deposits. This extends the life of the water tub. Still, you will need to replace the water tub every six months or so anyway. For this reason, it may be less important to extend the life of the water tub.

It’s fine to occasionally use tap water to clean your CPAP machine.

What You Shouldn’t Put in Your CPAP Humidifier

Remember that you are exposing your lungs to the water you put in the humidifier. This is a good reason to clean it regularly. Do not add substances to the water that might be harmful to breathe. Examples include:

PerfumesColognesScented oils

When cleaning your humidifier, don’t use:

Bleach Alcohol Chlorine Ammonia Moisturizing, glycerine-based, and antibacterial soaps

These substances could damage your lungs. You should also avoid using water softeners and descaling agents in the water tub.

What Water Should You Use When Traveling?

When traveling in areas with poor water quality, use distilled water in your humidifier. If the water is not safe for you to drink, it is not safe to put in your CPAP humidifier. In this case, using distilled water will limit your exposure to harmful substances.

For example, a few people in Louisiana who used tap water in Neti pots developed a rare infection of the brain caused by an amoeba. This condition is usually fatal and treatment is almost always ineffective.

The same risk has not been demonstrated with the use of a CPAP humidifier. Still, it is a good example of how dangerous microbes can sometimes be found in tap water.

Summary

Using the humidifier in your CPAP machine can help prevent problems in your nose and sinuses.

Outside of the United States, distilled water may be limited to specialty stores. In some cases you may need to buy it from a hardware store.

Some tap water may be safe to use in your CPAP humidifier, but the safest option is distilled water. Tap water sometimes contains minerals that will build up inside your machine. It may also contain dangerous microbes and chemicals.

Avoid adding things like perfumes or scented oils to your humidifier water. Avoid harsh cleaning agents when cleaning your device.

When traveling to areas with unsafe water, always use distilled water. 

A Word From Verywell

If there is any doubt about the safety or quality of the water supply, use distilled water in your CPAP humidifier. This is especially true if you are traveling in parts of the world where the water is unsafe.

If you don’t have access to safe water, you may want to consider using the CPAP without the humidifier.