Mask problems
CPAP Mask Leaks: Causes and Fixes
Most CPAP mask leaks come from three things: a mask that does not fit or was put on wrong, a cushion coated in skin oil, or air escaping through your mouth. Start by refitting the mask while lying down with the air on, wash the cushion, and replace worn parts. If leaks keep happening, ask your equipment provider about a different size or style rather than tightening the straps harder.
Signs
- Hissing or blowing sound from the edge of the mask
- Air blowing into your eyes
- Dry mouth, nose or eyes in the morning
- Red marks or soreness where the mask sits
- Your machine or app reports a poor mask seal or high leak
- Waking up often, or finding the mask off your face
Common causes
- Poor fit or wrong fitting technique
- A mask that is the wrong size, or one pulled on upside down or at the wrong angle, can leak badly. ResMed notes that masks often fit differently once you lie down and turn side to side, so a mask that seemed fine sitting up can leak in bed.
- Dirty cushion
- Skin oils build up on the cushion and stop it from sealing. A mask that fit well at first and started leaking days or weeks later often just needs more regular cleaning.
- Mouth leak
- If you breathe through your mouth and wear a nasal or nasal pillows mask, air escapes out of your mouth. ResMed lists this as one of the three most common leak causes, and it is more common on bilevel machines.
- Worn parts
- Cushions and headgear stretch and lose shape over time. Fisher and Paykel lists checking the mask for wear and tear as a core step, because worn parts may need replacing.
- Overtightened straps
- Pulling the straps tighter often makes leaks worse by folding or distorting the cushion, and it can cause marks and pressure sores.
Fixes to try, easiest first
Refit the mask with the air on, lying down
Put the mask on, connect it, turn the air on and lie down in the position you sleep in. Breathe normally for a minute, then adjust the straps evenly. Fisher and Paykel suggests pulling the mask gently away from your face and letting it reseat so the cushion inflates and settles into place.
If your machine has a Mask Fit feature (the AirSense 11 does), run it while lying down. It blows air at therapy pressure so you can find leaks before you fall asleep.
Loosen, do not tighten
If the mask leaks, your first instinct is to crank the straps. Try the opposite. Loosen them a little, reseat the cushion, and tighten only until the leak stops. ResMed warns that overtightening can cause discomfort, facial marks and pressure ulcers, and Fisher and Paykel says the same.
Wash the cushion every morning
Wipe or wash the cushion each morning with warm water and a very mild soap to remove the facial oils that break the seal. Wash the whole mask in mild soapy water once a week, and let everything air dry. Washing your face before bed helps too.
Check that you are wearing it the right way
Look up the fitting video or user guide for your exact mask. ResMed points out that people sometimes put masks on upside down or pull them on in the wrong direction, which causes big leaks.
Replace worn cushions and headgear
If the cushion is stiff, torn, yellowed or no longer springs back, or the headgear has stretched, the mask cannot seal well no matter how you adjust it. Check your mask's replacement schedule and reorder parts on time.
Deal with mouth leak
If you wake with a dry mouth while using a nasal or pillows mask, air is probably escaping through your mouth. A chinstrap can help hold your mouth closed, and a full face mask is another common answer. Ask your provider which suits you.
Ask for a different size or style with your clinician
Faces differ and there is no single right mask. If you have tried the steps above and still leak, ask your equipment provider or sleep clinic to refit you with a different size or mask type. Fisher and Paykel recommends this step when leaks persist.
Call your equipment provider or sleep doctor if leaks continue after refitting, cleaning and replacing worn parts, because large leaks can make your therapy less effective. Call sooner if you have skin breakdown or an open sore from the mask, if your device data shows your breathing events rising along with the leak, or if you still feel very sleepy during the day. Do not change your prescribed pressure to try to fix a leak; that is a decision for your prescribing clinician.
Supplies that can help
Pre-moistened wipes for a quick daily wipe of the mask cushion, mostly to remove skin oils between proper washes.
Plain, mild dish soap is the cleaning agent most CPAP makers and the FDA point to for masks, tubing and humidifier chambers.
Soft fabric liners that sit between your skin and the mask cushion to reduce skin irritation, red marks and the noisy leaks some people get from …
A soft strap that supports the jaw to help keep the mouth closed, used mainly with nasal and nasal pillow masks to reduce mouth leaks.
A pillow with cutouts or a contoured edge so a mask and hose are not pushed out of place when you sleep on your side.
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Mask types this applies to
Frequently asked questions
Is some air coming out of my CPAP mask normal?
Yes. Every CPAP mask has a vent that lets out a steady stream of air to flush away the air you breathe out. Fisher and Paykel notes that some leakage is normal for this reason. What matters is air escaping around the cushion edge, into your eyes or out your mouth.
Should I tighten my CPAP mask to stop leaks?
Usually no. Overtightening can fold the cushion and make the leak worse, and it can leave marks or pressure sores. Loosen the straps slightly, reseat the mask with the air on, and only tighten until the leak stops.
Why did my mask start leaking when it used to fit fine?
A dirty cushion is a common reason, since skin oils stop the silicone from sealing. Worn cushions and stretched headgear are the other usual suspects. Wash the cushion daily and check whether it is due for replacement.
Why does my mask leak only when I lie on my side?
Your face and the pillow change the mask's position when you turn. Fit the mask while lying in your sleep position, and consider a CPAP pillow with cutouts. Smaller masks such as nasal pillows often hold a seal better for side sleepers.
Sources
Last reviewed October 11, 2026. How we research · Report an error