Continuous Positive Airway Pressure (CPAP) therapy treats sleep apnea by providing a constant flow of pressurized air to keep the user’s airway open during sleep. Many modern CPAP machines include an integrated humidification system to add moisture to the pressurized air. This humidification significantly increases patient comfort by preventing dryness in the nasal passages, throat, and sinuses. The quality of the water used in this humidifier chamber directly affects both the therapy’s effectiveness and the machine’s lifespan.
The Short Answer: Is Boiled Water Safe?
The direct answer to whether you can use boiled water in your CPAP machine is no. Boiling water is an effective method for sterilization because the heat kills biological contaminants present in tap water. However, the function of boiling is solely to purify water from living organisms; it does not remove non-living dissolved solids.
Boiling the water does not alter the chemical composition of the dissolved minerals it contains. In fact, boiling causes some of the water to evaporate as steam, which slightly concentrates the remaining mineral content. Therefore, while the boiled water is biologically safe, its mineral load remains, making it unsuitable for the CPAP humidifier.
Understanding the Mineral Problem
The primary concern with using water that contains dissolved solids is the process of scale formation within the heated humidifier chamber. As the CPAP machine heats the water to create humidity, the pure water molecules turn into vapor and are carried into the air tubing. The dissolved solids, including minerals like calcium carbonate and magnesium, cannot vaporize and are consequently left behind in the water chamber. This residual mineral matter dries out and hardens, forming a white or grayish crust known as limescale.
Over time, this accumulation of scale damages internal machine components. The buildup can coat and damage the heating element or humidifier plate, which is responsible for vaporizing the water, leading to reduced humidification efficiency. Scale can also clog air passages or interfere with sensors that regulate temperature and humidity. Furthermore, damage caused by mineral residue from using non-recommended water is often grounds for manufacturers to void the CPAP machine’s warranty.
Why Distilled Water is the Only Solution
Distilled water is the only type of water universally recommended by CPAP manufacturers because it is free of both biological contaminants and inorganic dissolved solids. The process of distillation involves boiling water and collecting the resulting steam, which is then condensed back into a liquid state. This separation process leaves behind all impurities, including minerals, chemicals, and microbes.
The absence of minerals in distilled water means that when the water is heated in the CPAP humidifier, nothing is left behind to form limescale. This purity protects the sensitive mechanical parts and heating components, ensuring the machine operates at peak efficiency and its lifespan is maximized. While purchasing distilled water requires a small ongoing investment, it is an inexpensive measure compared to the cost of replacing a damaged humidifier chamber or the entire CPAP unit. Distilled water is readily available in large containers at most grocery stores and pharmacies.