Machine and humidifier
CPAP Water Chamber Leaking: What to Check
A CPAP water chamber usually leaks because it is not assembled or seated correctly, the seal is missing or misplaced, or the chamber is cracked. Reassemble and reseat it first. A cracked or damaged chamber should be replaced, and if water has spilled into the machine itself, unplug it and stop using it until it has been checked.
Signs
- Water on the table or under the machine
- Water pooling in the machine dock
- High leak message about the humidifier or side cover
- Hissing from around the water chamber
Common causes
- Chamber not assembled correctly
- The AirSense 11 guide lists an incorrectly assembled humidifier tub as a cause of a leaking tub.
- Cracked or damaged chamber
- The same guide lists a damaged or cracked tub or side cover, and says to contact your care provider for a replacement.
- Seal missing or out of place
- Philips lists a water tank lid seal that is missing or not properly seated as a cause of leaks.
- Overfilling or filling in place
- Filling past the max line, or filling while the chamber is in the machine, can spill water into the device. Fisher and Paykel advise fully removing the chamber before filling.
Fixes to try, easiest first
Unplug and dry if water got into the machine
If water has spilled into the machine itself, unplug it first. The FDA safety communication on DreamStation 2 lists water spilled into the machine as a reason to unplug and not use it. Contact your provider before using it again.
Take the chamber apart and reassemble it
Open the chamber, check the seal sits evenly in its groove, and close it until it clicks. Follow your user guide, since each chamber assembles differently.
Fill it away from the machine
Remove the chamber and fill it over a sink to the max line only. Then wipe the outside dry before putting it back.
Seat it fully
Slide it in until it clicks. On the AirSense 11, also check that the side cover is inserted correctly and clicks into place.
Inspect for cracks
Hold the empty chamber up to the light. Hairline cracks, especially at the base or hinge, mean it needs replacing.
Replace the chamber or seal
Water chambers and seals wear out. Get a replacement chamber made for your exact machine model through your supplier.
A leaking chamber is an equipment problem for your supplier. You do not need your doctor unless you have to stop therapy while waiting for a replacement. Most machines can run without humidification in the meantime, so ask your provider whether you can keep using CPAP dry rather than skip nights.
Supplies that can help
The removable water tank of a CPAP humidifier; it wears and needs replacing, especially if it cracks, clouds or leaks.
Distilled water is what most CPAP humidifier chambers are meant to be filled with, because it leaves little or no mineral scale behind.
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Mask types this applies to
Frequently asked questions
Can I use my CPAP if the water chamber is cracked?
Do not use a cracked chamber with water in it, since water can leak into the machine. Many machines can run therapy without humidification until a replacement arrives. Check your manual or ask your supplier.
What do I do if water spilled into my CPAP machine?
Unplug it right away and do not use it until it has been checked. The FDA lists water spilled into the machine as a reason to unplug and stop using a DreamStation 2.
Why does my CPAP say high leak when my mask feels fine?
On ResMed machines, a high leak message can point to a humidifier tub or side cover that is not inserted properly. Reseat it and check again.
Sources
Last reviewed October 11, 2026. How we research · Report an error