Distilled water is what CPAP manufacturers recommend for your humidifier chamber. Tap water carries minerals that leave scale and white buildup inside the tank and water path, which can shorten a machine's life and affect performance. Distilled water has those minerals removed, so it keeps the chamber clear of deposits. Note that distilled water is not a disinfectant: keeping mold and bacteria down comes from emptying the chamber daily, letting it air-dry, and washing it weekly.

Why distilled water for your CPAP

ResMed and Philips both recommend distilled water and advise against tap water, which leaves mineral buildup that can reduce performance over time. Spring, purified, and bottled drinking water still contain minerals, so they are not substitutes. For the full comparison, see tap water vs distilled water for CPAP.

Buy bottles or make your own

Sleeplay carries distilled water two ways: pre-filled bottle packs in 12 oz, 16.9 oz, and 20 oz sizes for grab-and-go refills, and the H2O 4 CPAP refillable pitcher with a replacement filter, so you can make CPAP-ready water at home and skip the bottles.

How to use and maintain

Fill the humidifier chamber to the line with distilled water before each night, and empty any leftover water in the morning rather than topping it off. Let the chamber air-dry during the day, and wash it weekly with mild soap and water. Replace the chamber on your manufacturer's schedule.

Traveling with distilled water

Small bottles are easy to pack, and TSA allows distilled water for CPAP as a medical liquid, though rules and airport availability vary. For the details on flying, see flying with a CPAP machine.

Cost and eligibility

Distilled water and the refillable pitcher are FSA and HSA eligible. See each product page for sizes, pack counts, and current pricing.