Your 3-Step Guide to Removing Calcium Deposits from Your CPAP Humidifier
Key Takeaways
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Prevention is Mandatory: Only use distilled water in your CPAP humidifier chamber to prevent calcium buildup and avoid potentially voiding your machine's warranty.
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The Safe Cleaning Agent: Use a solution of one part white vinegar to three parts distilled water to soak and dissolve mineral deposits safely without damaging plastic components.
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Know When to Replace: Replace your humidifier chamber every 6 months or immediately if you notice discoloration, warping, or cracks.
CPAP manufacturers suggest using distilled water in all CPAP machines and CPAP humidifiers. This measure goes a long way in keeping your CPAP equipment in good working order.
Sometimes non-distilled water is used. Non-distilled water contains contaminants. These contaminants bond together and stick on the surfaces of the humidifier water tanks. Continued contamination of the system will cause irreparable damage requiring the CPAP equipment to be replaced.
A non-abrasive cleaner can be used to clean the equipment. We suggest the following:
1. Citrus II - CPAP Mask Cleaner - a spritzer product
2. Citrus II - CPAP Mask Wipes - a disposable wipe product
In a pinch you can use vinegar and a soft bristle toothbrush is great to clean the water tank.
This post was updated with the latest information in November 2025.
If you use a CPAP machine with a heated humidifier, you may have noticed a flaky, white, or gray buildup on the inside of your water chamber. This is not mold or mildew; it’s mineral residue, commonly known as calcium scale or limescale, left behind when non-distilled water evaporates.
This buildup is more than just unsightly—it can:
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Damage the Humidifier Plate: Thick scale can interfere with the machine’s heating element, leading to ineffective humidification.
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Reduce Water Capacity: Scale takes up space, limiting how much water your chamber can hold and increasing the risk of running dry overnight.
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Void Your Warranty: Using tap water is against manufacturer recommendations and can void your CPAP machine's warranty if damage results from mineral buildup.
The simple fix is prevention: always use distilled water. However, if you already have scale, here is the best way to safely and effectively remove calcium deposits and restore your humidifier chamber.
The Essential Rule of Using Distilled Water
Why Distilled Water is a Must
CPAP manufacturers specifically recommend using only distilled water in all CPAP humidifiers.
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Tap Water, Bottled Water, & Purified Water: All contain minerals (like calcium and magnesium) and contaminants. When the CPAP heats the water, the pure water turns to vapor, leaving these minerals bonded to the heating plate and the plastic chamber walls.
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Distilled Water: This water has gone through a rigorous process to remove all minerals and impurities, ensuring that nothing but pure water vapor is created for your breathing air.
If you travel and cannot access distilled water: Use bottled spring water as a temporary substitute, but clean the chamber immediately upon returning home. It is not recommeded to not make this a regular practice.
3-Step Guide to Scale Removal
When that white, crusty buildup appears in your humidifier chamber, here is the most effective and manufacturer-approved method for safely dissolving the scale.
Step 1: Prepare the Vinegar Solution
Vinegar is a weak acid (acetic acid) that dissolves the alkaline calcium carbonate scale without damaging the plastic or metal of your chamber.
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Mix a solution: Combine one part white vinegar with three parts distilled water in a clean container.
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Pour into the chamber: Fill your humidifier water chamber with the vinegar-water solution until the scale is completely submerged.
Step 2: Soak and Agitate
Time is the key factor in dissolving hard scale.
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Soak Time: Allow the chamber to soak for 30 minutes to 1 hour. For extremely thick or stubborn deposits, you may need to soak it for several hours, or even overnight.
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Scrub Gently: Use a soft-bristled brush (like an old, clean toothbrush) or a specialty CPAP cleaning brush to gently scrub the remaining deposits. Do not use metal scrapers, scouring pads, or any abrasive materials, as this will scratch the chamber and allow bacteria to cling to the surface.
Step 3: Rinse Thoroughly
The final step is crucial to ensure no vinegar residue or smell is left behind.
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Primary Rinse: Pour out the vinegar solution and rinse the chamber repeatedly with warm tap water.
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Final Wash: Wash the chamber again using a specialized CPAP equipment soap or mild, unscented dish soap and rinse thoroughly one last time.
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Dry: Allow the chamber to air-dry completely before reassembling it into your CPAP machine.
*Tip: If the vinegar smell persists, fill the chamber with only distilled water and let it sit for a few hours before discarding the water.
Replace Your CPAP Parts Regularly
While cleaning can remove calcium scale, wear-and-tear and warping are solved only by replacement.
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Discoloration and Cracks: If your chamber has visible cracks, appears warped, or has become cloudy or yellowed, the plastic is degraded and it's time to replace it. Damaged plastic is a breeding ground for germs.
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Replacement Schedule: Humidifier chambers should be replaced approximately every 6 months to maintain optimal hygiene and seal integrity.
Cleaning the calcium out of your water chamber is simple, but preventing it is even easier. Make the switch to distilled water today to protect your CPAP investment and ensure you are always breathing the cleanest, most humidified air possible. If you have any additional questions, contact our customer care team at 866-414-9700.
