CPAP mask leaking: where leaks come from and how to check the fit

By SnorkelMatch, last checked October 10, 2026. How we check

A CPAP mask is supposed to let some air out, through its vent. A leak is air escaping somewhere else: past the edge of the cushion, into your eyes or out at the lip. Where it leaks tells you what to check. Here is what the makers’ troubleshooting guides say, in the order to try it, and when to hand it to your supplier.

Open the fit finder

Fig. 1A full face mask with its seal line dashed. Arrows mark common leak points: at the bridge of the nose toward the eyes, at the sides of the cushion, and at the lower lip and chin. The vent at the elbow lets breathed-out air out on purpose.

Some leak is designed in

Fisher & Paykel’s leak guide starts with this: “a certain amount of air leakage is normal to adequately flush out the air you are breathing out”^[1]. That air leaves through the vent, the small holes near the elbow in Fig. 1. The leak to deal with is the air that escapes around the cushion.

Signs your CPAP mask is leaking too much

Fisher & Paykel lists these signs of excessive leakage^[1]:

hearing or feeling air leaks “above what is intentionally necessary for exhalation”;
drying of the eyes, nose or mouth;
nasal congestion;
marks on your face or pain around your nose.

Its troubleshooting guide adds: “Waking up with dry, irritated eyes is a sign of excessive mask leak.”^[2] A noisy mask can be another sign of an insecure seal^[3].

Where it leaks, and what to check

CPAP mask leaking into the eyes

Air into the eyes points to the top of the seal lifting. ResMed’s troubleshooting guide says to first “gently pull the cushion away from the face to reinflate it” and reposition the mask; if the leak persists, adjust the straps that match the leak: “Leak in eyes: Top straps”^[4]. Size matters too. The American Academy of Sleep Medicine (AASM) says “a mask that is too small will not seal properly and air will leak out through the edges. The air may blow into your eyes.”^[5]

Leaking at the lip or chin

The same guide gives the matching step for the lower edge: “Leak on lip: Bottom straps”^[4], again after reinflating and reseating the cushion.

Leaking at the sides

ResMed lists a cushion membrane that is “creased or folded”, a cushion that is skewed or not inserted properly in the frame, and a mask that is the wrong size^[4]. Take the mask off, check the cushion is even and seated correctly as the user guide shows, and put it back on.

Nasal pillows

For pillows, ResMed says to “re-seat the pillows by positioning them just inside the entrance of the nostrils”, adjusting until they feel comfortable and secure, and adds: “Do not overtighten.”^[4] If a pillow still leaks, it may be the wrong size; ResMed suggests talking to your equipment provider^[4].

A fit check, in order

With the machine on, pull the mask away from your face and rest it back. Fisher & Paykel says to repeat this “until the mask seals well and feels comfortable”^[1].
Look for a creased, folded or skewed cushion, and reassemble the mask according to its user guide if needed^[4].
Adjust the straps evenly: top straps for leaks at the eyes, bottom straps for leaks at the lip^[4].
Do not overtighten. Fisher & Paykel says “a too-tight mask can distort the shape of components and cause leaks”^[3], and that the mask “should be worn as loose as possible without excessive leaking”^[1]. You should be able to get one finger under each strap^[3].
Do the final adjustment lying in your usual sleeping position^[3].

If you can only get a seal by tightening the mask until it is uncomfortable, ResMed says “you may have the wrong size of mask”^[6]. That is a question for your supplier. Over-tight straps also leave marks; see CPAP mask marks on your face.

Why a CPAP mask leaks at night

A mask can seal well while you sit on the edge of the bed and still leak at 3 a.m. ResMed explains: “a mask that fits well when you’re sitting up might not fit so well when you’re lying down,” because facial muscles change when you lie down and relax further in sleep^[6]. Its advice is to fit the mask “in your usual sleeping position”^[6]. NHLBI says the same in practice: adjust the mask every night while lying down with the machine on^[7].

On your side, the pillow can also push the cushion. Fisher & Paykel’s troubleshooting guide says to test how the mask feels “while lying in the position you normally sleep in”^[2]. The guide for side sleepers covers this in more detail.

Fig. 2Two heads lying on their side in a nasal mask. Left: a flat pillow presses on the lower edge of the cushion and air escapes there. Right: a pillow with a cut-out leaves room for the mask and hose.

A worn cushion leaks too

Fisher & Paykel’s own schedule says to replace a cushion on its interval “or if the cushion begins to leak constantly, becomes discolored or is torn”^[8]. ResMed’s US tip sheet lists signs of wear such as “You have to tighten the straps often”, “The mask has lost its spring” and “Mask seal is deteriorating or becoming more challenging”^[9]. The replacement schedule guide has the intervals.

When to call your supplier or doctor

“If you are experiencing persistent leaks or discomfort with your mask, talk to your healthcare provider,” Fisher & Paykel says; they can help with “different seal sizes or mask types”^[1]. NHLBI lists a mask that “does not stay on or fit well, or it leaks air” among the problems to raise with your provider^[7].

The same Fisher & Paykel guide lists checking that you are using the right pressure, and says to consult your healthcare provider if you are unsure^[1]. That check is for your sleep doctor. Never change your pressure or machine settings yourself to stop a leak.

If leaks keep pointing to the type of mask, the fit finder and the mask quiz list mask types to ask your supplier about, based on how you breathe, sleep and wear your facial hair.

Questions people ask

Is it normal for a CPAP mask to leak a little?

Some air is meant to leave the mask. Fisher & Paykel says a certain amount of air leakage is normal to flush out the air you breathe out, which is what the vent is for. What you want to reduce is leakage beyond that, around the edges of the cushion.

Why is my CPAP mask leaking into my eyes?

Air into the eyes usually points to the seal lifting at the top of the cushion, near the bridge of the nose. ResMed’s troubleshooting guide says to reinflate and reposition the cushion first and, if the leak persists, to adjust the top straps. AASM notes that a mask that is too small can leak and blow air into your eyes.

Why does my CPAP mask leak at night but not when I try it on?

ResMed explains that a mask that fits well sitting up might not fit so well lying down, because facial muscles change when you lie down and relax further in sleep. Make the final adjustment lying in your usual sleeping position, with the machine on.

Should I tighten the straps to stop a leak?

Only evenly and only a little. Fisher & Paykel says a too-tight mask can distort the components and cause leaks, and ResMed says needing an uncomfortably tight mask to seal may mean the wrong size. Reseat the cushion first.

When should I call my supplier about a leaking mask?

When the leak keeps coming back after you reseat and adjust the mask, when the cushion is torn, discolored or leaks constantly, or when you wake with dry, irritated eyes. Fisher & Paykel says to talk to your healthcare provider about persistent leaks; any pressure question goes to your sleep doctor.

Sources

[1]
Fisher & Paykel Healthcare (manufacturer): How to prevent CPAP mask air leaks
"a certain amount of air leakage is normal to adequately flush out the air you are breathing out"; signs of excessive leakage: "hearing or feeling air leaks above what is intentionally necessary for exhalation", "drying of the eyes, nose or mouth", "nasal congestion", "marks on your face or pain around your nose"; "It should be worn as loose as possible without excessive leaking."; "Reposition the mask by pulling it away from your face and resting it back again"; "Watch for wear and tear"; persistent leaks: "talk to your healthcare provider".; reposition "until the mask seals well and feels comfortable"; your provider "can help provide you with guidance on different seal sizes or mask types" Read on 2026-10-10.
[2]
Fisher & Paykel Healthcare (manufacturer): Troubleshooting guide for CPAP users
"mouth breathers can experience aerophagia when they use nasal masks. If this is happening to you, consider changing your mask style or wearing a chin strap."; "Waking up with dry, irritated eyes is a sign of excessive mask leak."; "Test how it feels while lying in the position you normally sleep in."; claustrophobia: "You may be better suited to a nasal, nasal cradle or nasal pillows mask. These have less facial coverage"; "we are unable to provide you with medical advice".; aerophagia "causes gas, stomach aches, bloating and belching" and the advice is to "Check your CPAP pressure with your healthcare professional"; "An ill-fitting mask can cause unacceptable levels of air leakage and that too can have a drying effect."; skin problems from "a buildup of sweat, oil, and dead skin cells accumulating on your mask and tubing" Read on 2026-10-10.
[3]
Fisher & Paykel Healthcare (manufacturer): How do I fit my CPAP mask correctly?
"Your breathing style, sleep position and facial features can change the fit and seal of your mask."; "Aside from nasal pillows, most CPAP masks come with sizing guides"; "Loosen the straps, place them over your head and then tighten them gradually."; "Check that you can get one finger under each strap – loosen if necessary."; "Lie in your preferred sleeping position to make final adjustments."; "A too-tight mask can distort the shape of components and cause leaks."; "Use a barrier on your skin ... a barrier cream, mask liner or gel pad"; signs of a poor fit: air "around your eyes, nose or mouth", noise, pain, "excessive lines, red marks or bruises"; "A nasal mask could be the best option if you breathe through your nose during sleep."; "There's no one mask that's best for everyone."; a full-face mask has "straps typically around your head and chin"; a noisy mask "can be a sign of an insecure seal and air draft"; "ensure that the headgear is adjusted to the same setting on each side" Read on 2026-10-10.
[4]
ResMed (manufacturer): Patient Information Guide: Mask Troubleshooting
"sizing across different masks is not always the same. Talk to your clinician to have your face size checked against the sizing tool/fitting template."; leaks at the bridge of the nose, eyes or lip: "Gently pull the cushion away from the face to reinflate it."; "Leak in eyes: Top straps"; "Leak on lip: Bottom straps"; "Cushion membrane is creased or folded"; "Headgear straps are too tight: Adjust straps evenly."; nasal pillows: "Re-seat the pillows by positioning them just inside the entrance of the nostrils ... Do not overtighten." Read on 2026-10-10.
[5]
American Academy of Sleep Medicine (AASM), Sleep Education: Continuous Positive Airway Pressure (CPAP)
"The CPAP mask may cover only your nose or both your nose and mouth. Another option is to use nasal pillows, which fit in your nostrils. Some other masks fit snugly under your nose."; "The mask must make a seal in order to keep your airway open through the night."; "Your sleep doctor will determine the amount of air pressure needed"; nasal mask: "the most common type of CPAP mask"; full face: "may cover your nose and mouth or may sit under your nose and cover your mouth. This type of mask may help if you have air leaks when using a nasal mask."; nasal pillows: "may help if you have air leaks or don't like the feeling of a mask over your nose and face."; marks or sores "are often due to a poor mask fit"; "Make sure your mask straps aren't too tight. It also may be helpful to buy soft CPAP strap covers"; "If the mask is too big, the straps holding it to your face will need to be pulled tightly"; "A mask that is too small will not seal properly and air will leak out through the edges. The air may blow into your eyes."; "try using a special bed pillow that is shaped for a CPAP mask and tubing"; "Begin using your CPAP for short periods of time during the day while you watch TV or read."; "Clean your mask, tubing and headgear once a week."; "Sometimes a mask style change is necessary to prevent dry nose, mouth or sore throat." Read on 2026-10-10.
[6]
ResMed (manufacturer): CPAP mask template and size guide
"The use of these templates is not intended to replace the advice of a medical professional, sleep technician or equipment supplier."; "ensure you are printing at the actual size by turning off all page scaling"; "If you can only get a good seal by tightening the mask until it's uncomfortable, then you may have the wrong size of mask."; "sizing across different masks is not always the same"; "a mask that fits well when you're sitting up might not fit so well when you're lying down"; "you should fit your mask in your usual sleeping position"; "Your mask should be as loose as possible while still creating a seal." Read on 2026-10-10.
[7]
National Heart, Lung, and Blood Institute (NHLBI), NIH: Living With Sleep Apnea
Talk to your provider if "You feel claustrophobic or are bothered by the noise" or "Your mask does not stay on or fit well, or it leaks air"; "Your provider may ask you to try different masks or nasal pillows"; "Clean your mask and wash your face before you put on the mask."; "Be sure to refill prescriptions on time for all of the device's parts that need to be replaced regularly, including the tubes, masks, and air filters." Read on 2026-10-10.
[8]
Fisher & Paykel Healthcare (manufacturer): Mask CPAP parts replacement schedule
Cushion: "Replace every fourteen days" (its nasal and nasal pillows masks) or "every thirty days" (its full-face masks) "or if the cushion begins to leak constantly, becomes discolored or is torn"; Frame: "Replace every three months or if the frame becomes discolored or cracked"; Headgear: "Replace every six months or if the headgear becomes discolored, stretches beyond adjustment or the hook and fasteners no longer latch." Read on 2026-10-10.
[9]
ResMed (manufacturer): Tip sheet: CPAP supplies and replacement parts (US)
"These replacement schedule guidelines are based on the current U.S. Medicare replacement schedule."; "Twice per month: Nasal mask cushions, Nasal pillows mask cushions"; "Every month: Full face mask cushions"; "Every 3 months: Mask frame systems"; "Every 6 months: Mask headgear"; replace when "You have to tighten the straps often", "The mask has lost its spring", "The silicone loses its grip and remains greasy, even after cleaning"; "we recommend contacting your insurance provider to make sure the parts you need are covered under your plan"; "Co-pays, deductibles and co-insurance may apply."; also "Your therapy feels less effective than usual" and "Mask seal is deteriorating or becoming more challenging"; "Replacing your mask cushions on a regular basis is important for hygiene"; headgear "can become stretched out and lose elasticity with regular use, which can lead to overtightening and discomfort" Read on 2026-10-10.

Last checked October 10, 2026. General information from official sources, not medical advice. Sleep apnea is diagnosed and treated by a doctor; do not change your pressure or settings yourself, and talk to your sleep doctor or equipment supplier before changing masks. CPAP masks are prescription devices; we sell nothing.