Cleaning and care
Distilled Water vs Tap Water in a CPAP Humidifier (and Using Vinegar)
Philips says to use distilled water in DreamStation 2 tanks, and ResMed says to use distilled water in the HumidAir 11 Standard tub and drinking quality water in the HumidAir 11 Cleanable tub. Distilled water reduces mineral buildup, and diluted vinegar (1 part to 9 parts water) removes buildup on ResMed tubs.
What the manuals say
Philips DreamStation 2: use only room temperature distilled water in the humidifier tank, and do not put chemicals or additives in it. ResMed AirSense 11: distilled water only in the HumidAir 11 Standard tub; drinking quality (potable) water in the HumidAir 11 Cleanable tub. ResMed's support FAQ for its Air series also says it recommends distilled water.
Your exact tub decides the answer. Check the label or user guide that came with your machine.
Why distilled water
Tap water contains minerals that leave white scale on the tub and heater plate and can cloud the plastic. Distilled water has had most minerals removed, so it leaves little or no residue.
Bottled spring or mineral water is not distilled and will still leave deposits.
Traveling or out of distilled water
If you run out, check your manual. Where drinking quality water is allowed, use it and clean the tub more often. Where only distilled water is allowed, skipping humidification for a night is an option; ResMed's Air series support FAQ says its machines work with an empty tub as long as the tub or side cover is inserted and humidification is turned off.
A waterless heat and moisture exchanger (HME) is another travel option on machines that support it, such as some travel CPAPs.
Using vinegar safely
ResMed's AirSense 11 guide allows washing the humidifier tub and outlet connector in 1 part vinegar to 9 parts water at room temperature, and recommends the same ratio to remove white powder deposits, followed by a thorough rinse.
Philips' DreamStation 2 manual specifies mild dish soap and water for home cleaning. Only use vinegar on parts and machines whose manuals list it, and never add vinegar to the water you breathe from.
Supplies that can help
Distilled water is what most CPAP humidifier chambers are meant to be filled with, because it leaves little or no mineral scale behind.
A heat and moisture exchanger (HME) that captures warmth and moisture from your breath and returns it on the next breath, used mostly with travel CPAPs …
The removable water tank of a CPAP humidifier; it wears and needs replacing, especially if it cracks, clouds or leaks.
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Frequently asked questions
Can I use tap water in my CPAP?
It depends on your tub. ResMed allows drinking quality water in its HumidAir 11 Cleanable tub, but specifies distilled water for its Standard tub, and Philips specifies distilled water. Tap water causes more mineral buildup either way.
Is boiled water the same as distilled water?
No. Boiling kills germs but does not remove minerals, so it still leaves scale. Follow your manual if it calls for distilled water.
Can I put vinegar in my CPAP water?
No. Vinegar is for cleaning certain parts, then rinsing. Philips says not to put chemicals or additives in the water tank, and you should only fill the tub with the water your manual specifies.
How much distilled water does a CPAP use per night?
It depends on humidity settings, room conditions and tub size. The AirSense 11 tub holds 380 mL. Many people use well under a full tub each night.
Sources
Last reviewed October 11, 2026. How we research · Report an error