Why Your CPAP Mask Leaks at Night (And How to Fix It)

Mask leak is the single most common complaint I hear from CPAP users. You wake up with a dry mouth, your eyes feel puffy from air blowing across your face, and your therapy report shows mediocre numbers despite wearing the mask all night. The good news is that mask leak almost always has a fixable cause.

The three most common causes of CPAP mask leak

1. A worn-out cushion

CPAP mask cushions are made of medical-grade silicone that slowly loses its flexibility over time. After about 3 months of nightly use, the cushion can no longer conform to the contours of your face the way it did when new. The change is gradual enough that you won't feel it happening — but your AirView data will show leak rates climbing week over week.

The fix is simple: replace your cushion every 3 months. If you're not sure when you last replaced yours, that's a strong sign it's overdue.

2. Over-tightening the headgear

This is counterintuitive, but tightening your mask straps actually makes leak worse. When you crank down the headgear, it distorts the cushion shape and creates channels for air to escape. The mask should rest gently against your face — firm enough to stay in place, but not so tight that it leaves deep red marks.

Try loosening your straps one notch and see if leak improves. For most patients I work with, it does.

3. Sleeping position shifts

Side sleepers and stomach sleepers often experience leak when their pillow pushes against the mask during the night. A CPAP-specific pillow with mask cutouts can make a significant difference — it allows the mask to sit naturally without pillow interference.

When to talk to a clinician

If you've replaced your cushion, adjusted your headgear, and tried a CPAP pillow but leak persists, the issue might be mask sizing or mask type. Not every face fits every mask, and a nasal mask that works beautifully for one person might leak badly for another.

That's where a clinical review of your therapy data helps. In a BreatheSession, I pull your AirView data and can see exactly when leak spikes happen, how severe they are, and what patterns suggest about the root cause. Sometimes the fix is as simple as switching from a medium to a large cushion. Sometimes it means trying a different mask style altogether.

Whatever the answer is, it's almost never "just deal with it."