Continuous Positive Airway Pressure (CPAP) therapy manages sleep apnea by delivering pressurized air through a mask. Many CPAP devices include an integrated humidifier to add moisture to the airflow, preventing dryness and increasing comfort. Manufacturers and medical professionals strongly recommend exclusively using distilled water in this humidifier. Using non-distilled water introduces significant risks, leading to mechanical issues with the equipment and potential health concerns for the user.
Understanding Water Composition
Distilled water is created by boiling water and condensing the resulting steam, a process that removes nearly all impurities. This results in pure H2O, free from minerals, chemicals, and biological contaminants. Tap water, conversely, contains Total Dissolved Solids (TDS), which are inorganic substances like salts, minerals, and metals. These often include calcium, magnesium, iron, or trace amounts of chlorine or fluoride added during municipal treatment.
Bottled water, such as spring or purified water, is also not a suitable substitute for distilled water in a CPAP humidifier. While safe for drinking, these types retain mineral content. Even purified water contains enough mineral residue to cause problems in the CPAP machine’s heated water chamber. Distilled water is the only common type entirely free of the mineral and chemical content that poses a risk to the equipment and user.
Impact on CPAP Equipment Longevity
The mineral content in tap or bottled water risks physical damage to the CPAP machine’s humidifier components. When the water is heated and evaporated, the pure water turns to vapor, but the minerals remain in the chamber. This process causes a buildup of hard, crusty deposits, known as scale or calcification, on the heating plate and the walls of the water chamber.
Mineral buildup reduces humidifier efficiency because the scale acts as an insulator, preventing proper heat transfer. This reduced efficiency means the machine struggles to provide the intended humidification, diminishing user comfort. Furthermore, the deposits can obstruct seals and small components, potentially leading to equipment malfunction. Using non-distilled water may also void the manufacturer’s warranty, as the resulting damage is considered preventable.
Health Implications for the User
Using non-distilled water introduces two primary health risks: microbial contamination and the inhalation of mineral particulates. Tap water is not sterile and often contains microorganisms such as bacteria, fungi, and protozoa, including species like Legionella and Pseudomonas. The CPAP humidifier’s warm, moist environment acts as an ideal incubator, encouraging these microbes to multiply rapidly.
When the CPAP machine aerosolizes the water, it turns these contaminants into tiny droplets inhaled directly into the lungs. Unlike the digestive tract, the respiratory system lacks a robust defense mechanism against these pathogens. Inhaling them can lead to respiratory irritation or serious infections like pneumonia. Additionally, mineral scale that forms in the chamber can become airborne, causing the user to inhale fine particulates that irritate sensitive lung tissue.
Short-Term Alternatives and Mitigation Strategies
In rare situations where distilled water is temporarily unavailable, such as during travel or an unexpected shortage, short-term alternatives can be used with caution. The best temporary measure is boiled and cooled tap water. Boiling tap water for at least five minutes and allowing it to cool completely before use kills most harmful microorganisms present.
Boiling the water does not remove dissolved minerals, meaning the risk of scaling and equipment damage remains. Therefore, boiled tap water should only be used as a last resort for one or two nights until distilled water is obtained. When using non-distilled water temporarily, the chamber must be emptied and thoroughly cleaned daily to mitigate microbial growth and mineral buildup. Users should switch back to distilled water immediately to protect their health and equipment longevity.