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A leaking CPAP mask does two things. It lets pressure escape, so your machine works harder to keep your airway open, and it blows air where it should not go: into your eyes, or out of your mouth. The good news is that most mask leak has a short list of causes, and your nightly data usually points to the right one.
Key takeaways
- Check your leak graph before you change anything: steady leak and short spikes have different causes.
- Fit the mask lying down, in your sleep position, with the machine running.
- Most fixes are free: a clean cushion, looser straps and a hose holder solve a lot.
Spot the leak in your data
Open last night in Apnealytics and look at the leak line. Leak is reported in litres per minute (L/min). ResMed machines flag a 95th-percentile leak above 24 L/min as a large leak; Philips machines report the share of the night spent in large leak instead, so the numbers are not directly comparable between brands. Our guide to CPAP leak rate explains the difference.
The shape of the line matters more than any single number.
| What you see | What it usually means |
|---|---|
| Leak stays high all night | Fit or cushion: refit, then replace the cushion |
| Short spikes that come and go | Position or mouth leak: check the hose and your jaw |
| Leak rises over a few weeks | A worn cushion or stretched headgear |
| Leak low, but dry mouth in the morning | Mouth breathing on a nasal mask |
1. Refit lying down
Masks are usually fitted sitting up, but your face changes shape when you lie down. Put the mask on, start the machine, lie in your usual position and adjust it there. Many machines have a mask-fit check that runs the pressure up so you can feel for leaks around the edges.
2. Replace a worn cushion
Silicone cushions soften and lose their shape with daily use. If your leak has crept up over a few weeks with no other change, the cushion is the first suspect. Many insurance plans cover a new cushion every month or so, so check before you pay out of pocket.
If leak got worse slowly, think cushion. If it got worse overnight, think fit.
A rule of thumb worth remembering
3. Loosen, don’t tighten
It is tempting to crank the straps when you hear a hiss, but over-tightening folds the cushion and opens new gaps. Loosen the headgear until the mask just seals at full pressure. A good fit should not leave deep marks in the morning.
4. Wash off facial oils
Skin oil and moisturiser make silicone slippery, so the cushion slides and lifts during the night. Wash your face before bed and wipe the cushion every morning with mild soap and water. Avoid alcohol wipes, which wear silicone out faster.
5. Stop mouth leak
On a nasal or pillows mask, air can escape through an open mouth. You will often see leak spikes with a dry mouth the next morning. A chin strap helps some people; others do better on a full-face mask. Your equipment supplier can help you try either, and our comparison of nasal pillows, nasal and full-face masks shows who each style suits.
6. Try another size or style
If you have refitted, replaced the cushion and still leak, the mask may simply be the wrong size or shape for your face. Sizing gauges are only a starting point, and most suppliers will let you swap within a set window. The free Mask Finder is a good way to narrow the choice before you try one.
7. Tame the hose
A hose that drags pulls the mask sideways when you turn over. Run it over the headboard or use a hose holder so it follows you, and make sure the swivel at the mask turns freely.
Not medical advice. Apnealytics is a tracking and coaching tool, not a diagnostic device. Machine-estimated numbers are not a clinical diagnosis; talk to your clinician about your therapy.
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Written by
Haniel Singh
Founder of Apnealytics. A CPAP user who builds software, not a sleep physician.
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