How to Avoid Water, Rainout, and Moisture in CPAP Tubing and Masks

As you sleep soundly, aided by the use of continuous positive airway pressure (CPAP), a sputtering noise begins and soon water is splashing you in the face through your mask, waking you up. Moisture in the CPAP tubing or mask is a frequent (and annoying) occurrence with the use of a heated humidifier.

Heated Tube for use with CPAP
Brandon Peters, M.D.

How can it be avoided? Discover how heated tubing, wraps, and changes in the humidifier setting may help to eliminate this occurrence.

CPAP Humidifier and Condensation

In most cases, moisture in the CPAP tubing or mask is secondary to the use of a heated humidifier. Without a humidifier in place, exhalation may also cause a small amount of water to condense within these plastic parts.

The heated humidifier increases the comfort of using CPAP, reducing dryness within the nose or mouth and making nosebleeds and infections less likely. There is a trade-off to introducing this additional water to the treatment, however.

When the humidity enters an unheated tube, the difference in temperature may cause condensation to occur. Small beads of water may form within the tubing. As these coalesce, rivulets of the water may make their way to the mask and splash your face.

The warmer the humidifier air—and the colder the tubing (or room)—the more condensation occurs. If the humidity setting is turned up, more moisture may be in the air to rain out within the tubes or mask. If you have the humidifier set to the highest setting, this is very likely to occur.

How to Avoid Moisture

What can be done to prevent this from happening? Any of the various options basically involve trying to closely match the temperature inside and outside of the tubing.

Use Heated Tubing

Perhaps the most desirable option is to use a heated tub (climate line) that delivers the warm, moist air from the heated humidifier to the CPAP mask. This will maximize the benefit of the humidifier.

All of the major manufacturers of CPAP equipment now offer heated or climate line tubing as part of their latest models. These have a heated coil that runs the length of the tube and keeps the air inside warmed.

The power is integrated into the back of the CPAP machine and the tubing easily connects to the various mask interfaces. In addition, it is possible to purchase a separate heated tubing component called Hybernite to use with older machines.

In general, it's recommended to set the temperature of the tubing between 78 and 82 degrees to reduce the likelihood of water forming in the equipment.

Change the Temperature Difference

A less expensive and simple option is to adjust the temperature of the heated humidifier or your bedroom. Turn down the temperature of the humidifier or turn up the thermostat in your bedroom. You may find that it is more comfortable to sleep in a cool room, so you might start by adjusting the humidifier.

Cover the CPAP Tubing

Another popular option is to put the CPAP tubing under the bed covers. This will warm the tube and reduce the condensation. There are also various fabric coverings sold that can insulate the tubing as well.

The most popular brand of tubing coverings is SnuggleHose. These come in various colors, patterns, and fabrics. If you are crafty, similar covers can be made easily with a long piece of fabric and a sewing machine or needle and thread.

Place the CPAP on the Floor

Another helpful option is to put the CPAP machine on the floor. By putting it in a lower position than where you are lying in bed, the moisture that does collect within the tubing will run back to the humidifier, rather than dousing you in the face in the middle of the night.

Finding the Right Solution

There are a number of highly effective options to reduce the condensation that can collect in CPAP tubing with the use of a heated humidifier. The benefits of the moisture largely outweigh the inconvenience, and a few accommodations will ensure that your sleep continues to be benefited by CPAP without any unnecessary disruptions.

If you continue to have problems, speak with your board-certified sleep physician or durable medical equipment provider about additional options that might be helpful to you.

Frequently Asked Questions

  • What is the best humidity level to avoid CPAP rainout?

    Generally, the best humidity level to avoid rainout on a CPAP machine is 3.

  • How do you remove water from CPAP tubing after cleaning?

    To remove water from CPAP tubing, run the CPAP without water in the reservoir to help push out excess water or hang the tubing until it air dries.

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3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. The Importance of CPAP Humidification. American Sleep Apnea Association. Published 2019.

  2. Nilius G, Domanski U, Schroeder M, Woehrle H, Graml A, Franke KJ. Mask humidity during CPAP: influence of ambient temperature, heated humidification and heated tubing. Nat Sci Sleep. 2018;10:135-142. doi:10.2147/NSS.S158856

  3. Rühle KH, Domanski U, Schröder M, Franke KJ, Nilius G. [Heated humidification during CPAP with and without tube insulation]. Pneumologie. 2010;64(5):316-9. doi:10.1055/s-0029-1244073

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