Replacement parts
Humidifier water chamber (tub)
The removable water tank of a CPAP humidifier; it wears and needs replacing, especially if it cracks, clouds or leaks.
Why it helps
A worn chamber can leak water or air, and a cloudy or pitted chamber is hard to keep clean. ResMed's AirSense 11 guide says to replace the tub if it is leaking, cracked, cloudy or pitted, or if the seal is cracked or torn, and lists a 6 month design life for the HumidAir 11 Standard tub and 2.5 years for the Cleanable tub. Medicare codes a replacement water chamber as A7046, with a usual maximum of 1 per 6 months.
How to choose
Chambers are model specific. The AirSense 11 guide says the HumidAir 11 Standard and HumidAir 11 Cleanable tubs are the only water tubs used with that machine; the Standard tub takes distilled water only, while the Cleanable tub can use drinking quality water and is designed for reprocessing. For any other machine, buy the chamber listed for your exact model.
Never fill above the maximum line, and do not move the machine with water in the chamber. Remove white mineral deposits with 1 part household vinegar to 9 parts water, then rinse with clean water, per ResMed's guide.
Frequently asked questions
How often should I replace my CPAP water chamber?
Medicare's usual maximum is 1 every 6 months. ResMed lists 6 months for the AirSense 11 Standard tub and 2.5 years for the Cleanable tub, and says to replace it sooner if it is cracked, cloudy, pitted or leaking.
Why is my CPAP water chamber leaking?
Common causes are a cracked tub, a torn or misplaced seal, or overfilling. ResMed says to replace a tub with a cracked seal or body.
Can I put my CPAP water chamber in the dishwasher?
For the AirSense 11, ResMed says the humidifier tub may be washed in a dishwasher at no more than 65 C. Check your own manual for other machines.
Sources
Last reviewed October 11, 2026. How we research · Report an error