Dry Mouth, Rainout & Leaks: Solving Common CPAP Side Effects
When you first start CPAP therapy, it can feel like you’re adjusting to a whole new world of equipment and settings. One of the most common questions we hear is:
“Why do I get dry mouth, water in my tubing, or annoying air leaks?”
Let’s break it down step by step.
Why We Use Humidity on CPAP (Though It’s Not Mandatory)
CPAP therapy delivers pressurized air to keep your airway open, and for many patients, that airflow can feel dry and irritating. That’s where the built-in heated humidifier comes in—it adds moisture to the air, making it gentler on your nose, throat, and mouth.
But here’s the thing: humidity needs vary depending on where you live.
Is It Bad to Use CPAP Without Humidity?
Not necessarily. Some patients never use the humidifier and feel perfectly fine.
Pro Tip: If you have a travel CPAP like the Transcend Micro, you can use a Heat-Moisture Exchanger (HME)—a waterless humidification system that traps and reuses your own exhaled moisture. It’s an extremely effective method widely used in hospitals around the world. Best of all, it lets you travel light, with comfort, and without worrying about finding distilled water jugs.
Why Cleaning the Water Chamber Really Matters
Do you have to clean your CPAP chamber? Technically no.
Should you? Absolutely.
The reason: warm, moist environments are breeding grounds for bacteria and fungus. You may not see it, but growth can begin within days.
Even if you use distilled water (which prevents mineral buildup and keeps your chamber looking clear), bacteria still enter from your own breathing. Cleaning prevents those hidden colonies from forming.
Pro tip: Empty your chamber daily, wipe it down, and give it a weekly wash with warm soapy water.
A word of caution: Be careful with what you read in Facebook groups or online forums. We often see patients come in with equipment that they thought was “cleaned regularly,” but it tells a very different story:
Neglected cleaning can lead to chronic irritation, recurrent sinusitis, skin rashes, and upper-airway infections. Maybe some patients do suffer from these symptoms without realizing their dirty equipment is the culprit.
Our point is simple: follow the recommended cleaning guidelines for best outcomes. It’s not just about appearance—it’s about your skin health, preventing infection, and keeping therapy safe. For Quick Daily wipe-downs consider the Contour CPAP Mask Wipes on sale!
The Dreaded “Water in the Hose” (a.k.a. Rainout)
Few things are as frustrating as waking up to that “thump, thump” gurgle in your CPAP hose. That’s rainout—condensation forming inside the tubing.
Why does it happen?
Science 101: Think of a warm summer day. The hotter the air, the more water it can hold. When temperatures drop (like at night with the window open), water condenses—just like dew on the grass.
Common Causes of Rainout
If you haven’t changed your settings but suddenly notice condensation, here’s what may be happening:
How to Fix It
✅ Use a heated hose – keeps the temperature consistent, preventing condensation.
✅ Use a Hose Cover like the Joey Hose Cover
✅ Adjust humidity settings – lower the level until the rainout stops.
✅ Keep tubing off the floor – use a hose lift or run it over the headboard so water drains back toward the chamber.
✅ Warm up your room slightly – a freezing room + warm humid air = instant condensation.
What About Dry Mouth and Leaks?
✅ Dry mouth is often caused by air escaping through your mouth during sleep (especially if you’re using a nasal mask). A chin strap or switching to a full-face mask can help.
✅ Leaks happen when the mask doesn’t seal properly. This could be due to poor sizing, worn-out cushions, or sleeping position changes. Regular replacements and professional fittings are key.
✅ Increasing humidity is one way to offset dryness. However, if you’re constantly waking up dry and blowing through your entire water chamber overnight, something isn’t right:
✅ The machine may need to be checked for pressure delivery or humidity function.
✅ The mask may need refitting or replacement, depending on wear and tear.
Remember: It is not normal to have persistent dryness. It’s a side effect of therapy that isn’t optimized.
Pro Tip: Ask yourself whether dry mouth is new, or if you had it even before CPAP therapy. Many medications can severely reduce saliva production, which can worsen dryness and make it feel like a CPAP issue when it’s actually medication-related.
The Bottom Line
CPAP therapy is life-changing, but small annoyances like dry mouth, rainout, leaks, skin irritation, and sinus issues can make it harder than it needs to be. The good news? With the right adjustments—and sometimes just a heated tube—you can get back to restful, uninterrupted sleep.
At SleepEZ Home Health, we specialize in helping patients troubleshoot side effects, find the right mask fit, and make therapy as comfortable as possible.
