What is CPAP Rainout and How Can it be Prevented?

Have you ever woken up to water in your mask?
Ever noticed a lot of condensation in your tubing?
Has water in your hose ever stopped you from using your CPAP?

This is known as CPAP rainout. What is rainout? And why does it happen?

What’s the big deal with moisture in the air?

The normal function of the upper airway is to heat, humidify and filter the air that you breathe into your lungs.

If you have been diagnosed with sleep apnea and are using CPAP (continuous positive airway pressure), the device is blowing air into your airway all night long and you may have some leak of air through your mouth or mask (learn more about how CPAP works here or click the image below).

This can cause dry airways and inflammation.

Studies show up to 70% of CPAP users experience nasal congestion, dry nose and throat, sore throat, nose bleeds (epitaxis) or discomfort from the cold airflow CPAP (read more about the benefits of heated humidification here).

Heated humidification can reduce airway dryness and increase compliance.

What causes rain out?

If, like most CPAP users, you’re using a heated humidifier, the air is heated in the humidifier and flows through the tubing up to the mask and into your airway. As the air travels through your tubing, its temperature drops rapidly.

As the air cools, the moisture from the air condenses into droplets inside of the tubing.

The tubing can fill with water.

The water can flow down the tubing and into your mask.

This is condensation of the humidified air and is often known as “rainout.”

Solutions for CPAP rainout:

1. Move your CPAP machine

Move your CPAP machine to a lower level than your mask. Use gravity to your advantage so that the condensation does not flow to your mask.

If your CPAP is on a bedside table and the tubing drains down to your mask, try moving your machine onto a lower surface so the tubing and air flows up. If water droplets do form, they will flow back down to your humidifier and not into your mask.

2. Try wrapping your hose to keep the air warm

Wrapping the hose using specially designed tubing wrappers can help to insulate the blowing air from the lower temperature of the room, reducing “rainout.”
You can even run the tubing beneath your blankets to keep it warm.

3. Adjust the temperature in your bedroom

It’s the difference between the temperature in your bedroom and the temperature of the air in your tubing that causes the rainout. If your room is really cold at night, you’re more likely to see condensation in your tubing.

4. Adjust your humidifier settings

Talk to your equipment provider about changing your humidifier settings. If you live in a warm or very humid climate, you may not need a high temperature setting. The humidifier is trying to warm the air to around 80 degrees Fahrenheit.  

5. Use heated CPAP tubing

Heated tubing reduces rainout by keeping the temperature of the air constant as it travels from the humidifier to your mask. If the air stays warm, it doesn’t condense into droplets.

Heated tubing is designed to manage humidification in real-time based on changes in the climate in your bedroom, such as increases or decreases in temperature or humidity, and changes in your CPAP pressure and mask leak.

Check out ClimateLine heated tubing here (it is covered by most insurance-learn more about insurance coverage for supplies here).

Have you experienced CPAP rainout and think you may benefit from heated CPAP tubing?

Order ClimateLine Tubing


Other posts you may find interesting:


  1. Tim Birdwell Reply

    I have been experiencing rain out since I’ve started this treatment in December 2018. I have the heated tube, and use to keep everything on auto. Then I started using manual , but don’t know what settings to run it on. Still getting Rail out. My cpap does sit on my night stand, which is head level , but I have the tube ran over top of my head board and I still get rain out. Maybe I need to put it on the floor, keep the hose going up over head board, and put settings back on auto.

    • Hana Reply

      Hi Phil, I am having the same issue. i have used my CPAP for a couple of years with no issues and within the last 6 weeks I have experienced ‘rain out’. did you find a solution? I am open to anything that will help.

  2. Dave Reply

    I have had “rainout” at times with my cpap machine. The noise of the water in the tube has caused me to wake a few times. What found that has helped is that I cut up an old t-shirt and rapped the tube using paper medical tape about every 6 inches to insulate the tube. It’s free and only takes a couple of minutes, and beat paying $25+ for a cover.

  3. Laura Brunetti Reply

    Thank you Dave

  4. Phil Reply

    For the first year – great. Now no matter the setting I get drenched. Have new heated tube – 72 room temp- auto setting or manual at any temp – no luck. Added a tube cover. Nothing has worked. Machine below head level. Help!!!!!

    • Kathryn Albert Reply

      Hi Phil, I am having the same issue. i have used my CPAP for a couple of years with no issues and within the last 6 weeks I have experienced ‘rain out’. did you find a solution? I am open to anything that will help.

  5. Sierra Reply

    With the AC on, I got a lot of rainout from my BiPAP until a couple of weeks ago. The large amounts of water woke me up and even resulted in a gurgling noise from the hose which kept me up. I took the hose outside and gave it the ol’ “lasso” treatment (swinging it overhead to remove the water via centrifugal force- it’s a 6′ tube so only swing from the middle, doing half at a time unless you have the strength and speed to get the whole thing going at once. I don’t. ‍♀️) After I emptied the tube with my lasso skills, and gave the neighbors quite a show, I’m sure, I wrapped my hose with a couple of ace bandages I bought from the Dollar Tree and used tape to secure them along the way. The tape is only on the actual tubing in small parts on either end to keep them from slipping. So far so good! And much cheaper than expensive hoses and covers and easy to remove!

  6. Leonard Zamkoff Reply

    With a turned off Soclean connected to a resmed airsense 10, the water in the humidifier tank bubbles with each intake of breath. This didn’t happen when I had a philips CPAP. Is the water bubble normal? The Soclean is off, so should be contributing no air to the tank.

  7. Brenda Reply

    I have a SoClean and a Resmed Airsense 10 as well. The water bubble is not normal. It should be nice and quiet. (Other than you can hear each breath of air as with every CPAP) I’m not sure why it is doing that for you. I would just double check the thin black hose to make sure it is pushed on tight to the water chamber. I do remember that adding the Soclean machine I needed at different water reservoir lid that allows the thin black tubing to be attached to it. I would call Resmed if you can’t figure it out…there should be no bubbling noises at all.

    • Kimberly Sue Reed Reply

      My Cpap machine is pulsating air into my nose pillow cushion. It’s cutting off my ability to be able to breathe through the nose cushion with my mouth closed.

      What am I doing wrong? Do I need to change the nose cushion again?

  8. Jeremiah Reply

    I had at to fight for air! Woke up not just to bubbling as water splashes but felt hard drawing in air!. I looked it up found this. Hope o van fix it.

  9. Lori Reply

    I’ve been using a cpap machine for years and every winter i experience what ya’ll refer to as rain out. Because i don’t have the fancy cleaning machine i clean my tubing and mask while taking a shower – about 2-3 times per week. I want to try wrapping the tubes to prevent rain out, but I can’t imagine having to uncover then cover the tubing each time. Cleaning is very cumbersome already.

  10. Mary Reply

    I been having rainout, i have the rubing wrapped as instructed by Doctor, still have the same problem, i had cpap on headboard, moved it to night stand, then moved it to floor still have rainout, i dont know what to do. This has been going on over a month.

  11. Uma Reply

    For ResMed Apap machine what does 3 or 4 or 5 stands for humidification? I want to know how much percentage of humidity is 3 or 4 or 5

  12. James M Courtney Reply

    Seeing zero replies to any of the posts on this blog, makes me think there is no remedy coming from this blog, therefore useless, no help.

  13. Sakthivel Reply

    I have been using with heated tube for the past 8 months and it was working fine. Last night, I heard water bubbling in tube and had rain out. I heard the bubble sound even after turning of the machine. I also found water in the tube. Please help. I am unable to use the machine.

  14. Kenneth Reply

    I am having the same issues with a rainout and haven’t found a solution. However, I have for the bubbling noise issue. I have found that if I pull the (water container or whatever it’s called) completely from the machine and then put it back it solves my problem. This has worked every time it’s happened to me. Hope it helps y’all as well.

  15. Robert J Lima Reply

    Rainout is the single most frustrating problem at certain times of the year and room conditions. I’ve tried everything suggested with no consistent help. Isn’t it time the CPAP engineers get a handle on this and FIX this problem ?

  16. Eric Reply

    I have a Philips machine sitting just below head level with the heated tube running down towards the floor and back up to my nasal mask and still waking up to moisture build-up in my mask tickling my nose. I’ve got the tube temp set to max and now the humidifier set to 1 and will try just turning it off tonight. Is it possible that the source of the moisture may actually be from the air I’m exhaling from my nose?

  17. G.W. Reply

    I have been using a Phillips Respironics Dreamstation since March 2020. I have had a few Rainout issues that may have been self induced. I like to sleep in a cool room and as i live in an apt that faces the south, i have to deal with room temps fluctuating based on seasons and outer apts as i am in the middle of 3. To compensate i have a fan that sits in the hall but blows into the bedroom. I am also a side sleeper both left and right, with a full headgear Airfit F20 mask and standard non heated hose. My dreamstation is on a bedside table and the hose runs down between the table and bed then back up and over my shoulder to the mask. It was a cool night when i went to bed and woke up to a foggy morning outside, so i am thinking that perhaps my fan and the outside temp change may have contributed to this rainout. I am thinking about a hose hanger to help elevate the hose which should allow the condensation to flow back into the tank.

  18. Victoria Casias Watson Reply

    I am ready to stop using the CPAP. I have all the bells and whistles and still have “rainout” Help… This has been a journey since May 2020. Right now I am wrapping my tube with Ace bandages and hoping this will be the answer. I have little hope tho… My doctors says I have Severe Apnea. I am thinking I would be able stay asleep if I just don’t use this machine… Yikes.

  19. Shaun G. Reply

    I have my airsense 10 set at 70 and I leave the ramp and humidification setting on auto. Our room is cool but not very cold I find if I try to switch to manual settings I am more likely to get rain out. I read if you have rain out issues you could try running the tubing under your blankets and see if that helps.

    My device sits on the floor and I clean my mask and tubing with warm water and liquid baby soap.

  20. Thomas Reply

    Is there any solutions to rainout!

  21. Adrian Morandin Reply

    With all the machine resmed manufactures no one as told them this huge problem with rainout they must know, what are the engineers waiting for you can put a man on the moon, can’t fix the rainout issue.

  22. Alison Reply

    The solution to rainout is ………..
    Don’t put water in the chamber. You can still use the heated tubing, just turn off the humidity and the tube temperature to off so it doesn’t burn the chamber. I have been doing this, for almost 2 years now , due to the fact of rainout. If my room is cold, I do try to put the tube under my covers so the air in the mask isn’t cold. It works and I am still alive and haven’t had any issues in respect to sinusitis, colds , etc.

    • Melissa Reply

      This was the fix for me too. Nailed it.

      • Bob Reply

        Don’t you get a burning smell though with no water in the tank? I was fine for 3 years until I received my replacement Dreamstation this summer, then bam, last week this rainout starts!

  23. Susan Willey Reply

    My husband is having issues with fluid around his heart and also fluid in his lungs. He has been having problems with shortness of breath and not being able to do very much or even walk across the room without running out breath. I woke suddenly last night with the idea that the rainout could be causing the fluid in his lungs. Could that be a possibility? I know that the C Pap forces air into his lungs. So, could he be breathing in the water, causing the lungs to absorb fluid? Could the C Pap be forcing the water from the rainout into his lungs?
    Thank you for any suggestions you can give.

    • Kathi Bachor Reply

      Susan, I would definitely be calling his Dr on that issue to see if that could be causing fluid in his lungs. Rain out has become a huge issue for me. I’ve used my Philips Responics bipap machine now for 3 years and this winter was the first time I ever had rain out. My sister Purchased a zippered tube cover from Amazon for me, it’s kinda helped. I will try doing a hanger for the time so it has to flow up first and then to me (thanks to one of the suggestions). I’ll post back on here in a week or so to let you know how it goes. This is a great way to chat about issues. Also, my machine separates from the humidifier, so obviously you don’t have to use it, if this hose cover doesn’t work, I may just remove it for the winter months. Thank you for suggestions.

      • rorider Reply

        I use a hanger for the hose (up and over the headboard) and have a cover as well. I still get rainout that wakes me and prevents me from returning to sleep. I am looking for a solution to this as I really can’t sleep with the excessive moisture draining onto my face. I use nasal pillows and really like them.

  24. RJ Reply

    I have been using a CPAP for two years, and have just recently started to experience the rain out there has been mentioned in the above post. It wasn’t until I turned my pressure from 12 to 14 that I begin getting the gurgling in the hose no matter what humidity level I set the machine to, if I set it at one I get very little humidity or gurgling if I put it on two or above It gets to the point where I can’t even breathe through my hose that sounds like I’m snorkeling. my room is always very cold and this was never an issue until I turned up my pressure now even on Level one of humidity it seems to blow or evaporate all the water out of my tank in one night.

  25. DJ Reply

    So, the noise I am getting is called rain out? I need to know how to correct this I have had the CPAP for a couple years now, and this sound just started this year so I stopped using machine but need to use it so I can get decent sleep, help!

  26. Henry Reply

    This is really frustrating to live with rainout. I have used ResMed for a couple of years, and rainout just started a couple of weeks ago. I will see if increase the room temperature would help to fix it.

  27. Cheryl Reply

    I like my room cool for sleeping. I had to turn off automatic functions as they made rainout worse. I have a heated hose, but hate breathing hot air. Woke up last night drowning as my nasal pillows poured water into my nose. Unit is on side table and hose is high over my headboard. Guess the humidity gets set back to 1 and I’ll just keep saline gel in my nose!

  28. Timothy Fauble Reply

    I need a high level of humidity. I run my resmed 10 humidity at 7 and sometimes 8. I found that if I point the elbow of the hose that connects to the machine straight up, and keep my hose closer to me, usually under my arm and then down my side and up to my face, I won’t have rain out. I’m currently on setting 7 and my hose is nestled next to me with my machine right next to the bed, head level. No gurgles. Haven’t had any for a while. Cuddle your hose not your hoes I guess

    • Teresa Reply


    • Teresa Reply

      My rainout is worth reading this reply. bah haha

    • Mikal Mullaly Reply

      LOL. Nice.

  29. Charles Roberts Reply

    My wife recently started using a humidifier in our bedroom where I sleep with a Cpap. Ever since then my tubbing and mask are always filled with moisture and makes whistling noises. I’ve tried turning the humidifier off and even running the Cpap without water, but there is still moisture in the tubes and mask. Is it possible that my wife’s humidifier is putting moisture into my Cpap tubbing and mask, and how do I stop it? Thanks

  30. Karen Reply

    I have been having rainout too. If the gurgling wakes me up in the middle of the night, I just disconnect the hose, hold the center of the hose with my left hand, and twirl it 8 inches from the middle like a lasso with my right hand several times so the 2 ends are getting the most centrifugal force. This makes the water come shooting out! Then I plug it back in and go back to sleep. No more issues the rest of the night. I have found that if I (every morning) disconnect the hose and let it hang over a door so that the water, that accumulates during the night, drips out and dries. This helps me most nights from having to take care of it during the middle of night.

  31. Kerry Cassetti Reply

    I don’t use the heated tubing ( too hot for me) and no water in the reseverior only thing that works for me.

  32. Stephanie Reply

    Has anyone tried a “dehumidifier”? I can’t afford one at the moment. But I have a lot of rainouts almost nightly! It is so frustrating! I am almost to the point of where I will stop wearing it the rest of the night if it happens.

  33. Kay Thoreson Reply

    I appreciate reading these suggestions. I like a cool room (thermostat at 60-63, door/window open slightly, and a cool hose, but then I get gurgling rainout . . . so I keep adjusting the settings on my ResMed AirSense 10. I have the hose heat turned off, and the humidity to 3;
    air pressure is 11. Without the humidifier at all, it is too dry.

  34. Linda Andrews Reply

    Two months ago, a week into using my CPAP, the gurgling in the tube and the water in my nose were driving me crazy! (My bedroom is unheated and is very cold in winter.) Having my machine lower than my mask did nothing to alleviate the situation, so I just ditched the humidifier completely. (I replaced it with a flat end panel.) Big improvement! Haven’t used the humidifier since and have had no problem with dryness of any kind. (I’m a nose breather so I have a nasal mask only.)

  35. Kristina Harper Reply

    I removed my hose, drained the water out of it, filled the reservoir since it was very low and reduced the humidity to 1. It fixed the problem. I keep my room chilly and my hose temp I had just changed from 80 to 76.

  36. Al Reply

    You need to mention that a frequent cause of rainout is a low point on the hose that allows moisture to condense. The hose should always be elevated. The two lowest points in the hose should be the machine and the mask.

  37. High Rated Gabru Reply

    Great info. Thanks for share!!

  38. Charles Reply

    Just wondering, is it possible to breathe in the water during a rainout before the water wakes you up from splashing you in the face through the mask? I can handle the rainout and fix it whenever it happens but when it happens every so often do you or can you breathe in water every time this happens before it wakes you up?

  39. Simon Light Reply

    How come there’s never any answers from technical??

  40. kat Reply

    Omg I think I figured it out. Machine on the floor and dont have the hose going over the head board. Fixed in 2 minutes.

  41. deedee Reply

    I apparently experience rainout as well – although I never heard about it until just happening to find this site. Thank you all for finally telling me why I had water coming out of my mouth in waves and bubbles.

  42. Mary Reply

    I have rainout in my mask even without using the humidifier. My room is kept cool. I purchased a ResMed tube wrap and moved the CPAP machine to the floor and sleep with tubing under the covers. Still wake up in middle of night with water in my face. Looks like no one from the manufacturers are responding to the comments on this site. We are lucky that fellow CPAP users are sharing their experiences. It would be nice if someone has a solution to the rainout since we can’t get a good night rest.

  43. SJ Reply

    Hello Everyone, Great to read about your experiences. I have been using a CPAP for 7 years now (without a humidifier) and have only experienced rainout during the last 5 months. But rainout happens about twice a week. I have tried many of the things suggested – keeping the Resmed machine on the floor, got an insulation for my tube, clean my tube and mask regularly, keep the window closed and generally have a warm room (live in London) through central heating. I tried using a humidifier but felt it very uncomfortable and had difficulty in breathing and had to gasp for air!!! So gave up on that. What surprises me is why it is happening after all these years? I have been living in the same country and sleeping in the same room but this problem has come up only during the last few months! Any help or suggestions would be most welcome. All the best everyone. Take care.

    • Cherylea Obrien Reply

      Hi there, this is what has been posted multiple times I have read a few people say they previously had no issues for years and suddenly in the last 6 months they have been getting rainout! Have they changed the machines in some way? Is there more moisture in the air all over the world? Something must have changed to get this wide spread change! Very interesting. By the way people I have had my machine 3 nights have noticed the water in my tube and on my face, leaking around the joins and waking me up it going into my nose, I quickly rip it away and stop using it either by getting up or going without it for the surest of my sleep, it is dangerous, today I have a sore throat and my tummy has been feeling pain , my lungs feel like there is fluid in them, so I’m only mildly sleep apnea and can afford to stop using the trial machine, I’d rather snore and sleep in seperate room then end up with pneumonia which is exactly what is happening here, the water is being pumped up the nose. I have filled my water every day about 50 mls so where had it gone? Up my nose like a rubber hose says Vinnie Barbarino! Maybe it’s just another way the government and scientists/ medical industry is trying to kill off the masses? Go dry people, don’t use the vapourizor is my guess, but don’t go drowning yourselves either! Otherwise you will sleep, and never wake up!

  44. happy wheels Reply

    I appreciate your ideas and writing style!

  45. Diablo Reply

    Get rid of ozone cleaners such as soclean, ozone destroys lung tissue…it’s a dirty little secret!

  46. Carolyn Anderson Reply

    Comments very helpful

  47. Melinda Reply

    My machine is brand new and I’m getting rainout. I didn’t know what it was either. No one seems to want to help. The machine I used as a trail was fine. Now I’m waking up in the middle of the night not being able to breath in a panic. It’s terrible

  48. Roxie Reply

    Hello from SC….yes, I have had the same similar problems with rainout….so annoying. Contact your Technical person at your DME (Durable Medical Equipment). They are trained to help with this situation. I know how frustrating it is. God’s Blessings and go away rainout.

  49. The CPAP Source Reply

    The blog post describes in detail what CPAP rainout is and how it can be avoided. The text is clearly written and explains everything you need to know to avoid rainout. This post looks to have been authored by an expert on the topic, as the information offered is both timely and correct.

    • Gregory Trachta Reply

      Your blog post ignores the problem raise by several of your questioners: Rainout is occurring with NO humidfier tank (or an empty tank). It seems to start after about a year of therapy. None of your solutions address this problem being experienced by many people. It’s some kind of wearout problem in the exhale diaphragm.

  50. Pam Reply

    Can someone explain the difference between adaptive humidification and fixed humidification?

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