A Continuous Positive Airway Pressure (CPAP) machine is a medical device that uses air pressure to keep a user’s airway open during sleep, often incorporating a humidifier to prevent the pressurized air from drying out the nasal passages and throat. The humidifier introduces moisture into the air stream, which requires a specific type of water to function correctly and safely. Manufacturers of these devices strictly instruct users to only use distilled water in the humidifier reservoir. This requirement is necessary for both the long-term functionality of the machine and the user’s health.
The Mechanical Imperative: Stopping Mineral Deposits
The primary threat to the CPAP machine from using non-distilled water is the presence of dissolved inorganic minerals, such as calcium, magnesium, and iron, which are common in tap water. When the humidifier heats the water to create vapor, the pure water evaporates, leaving these heavier mineral compounds behind in the reservoir. This process is known as scaling or mineral buildup, which forms a chalky residue that coats the heating plate and the interior of the water chamber.
This residue acts as an insulator, significantly reducing the efficiency of the humidifier. The machine must work harder to achieve the required level of humidity, shortening the lifespan of components and increasing energy consumption. Severe mineral scaling can eventually obstruct small parts, leading to machine malfunction and potentially voiding the manufacturer’s warranty.
The Health Imperative: Eliminating Airborne Contaminants
The warm, moist environment of a CPAP humidifier provides an ideal breeding ground for microorganisms found in non-distilled water, posing a direct health risk. Tap water, while safe for drinking because stomach acids can neutralize many pathogens, is categorized as “unsterile.” When this water is aerosolized by the CPAP, any bacteria, fungi, or protozoa present bypass the body’s natural defenses and are delivered directly into the lungs and sinuses. Pathogens such as Pseudomonas aeruginosa and Legionella species can thrive in these conditions.
Inhaling these contaminated aerosols can lead to respiratory infections, ranging from sinus irritation to severe conditions like pneumonia. Additionally, tap water often contains trace chemicals like chlorine or fluoride, which are added for public water treatment. When these chemicals are heated and inhaled as a vaporized mist, they can irritate the sensitive lining of the respiratory tract, potentially causing inflammation or discomfort.
Understanding Distilled Water Versus Other Options
Distilled water is created by boiling water into steam and then re-condensed. This vaporization and condensation cycle leaves behind virtually all impurities, including minerals, chemicals, and microorganisms, resulting in water with a near-zero total dissolved solids (TDS) count. This purity prevents both mineral buildup and the proliferation of pathogens, making it suitable for medical devices. Bottled drinking water, even if labeled as “purified,” is not a safe substitute because it still contains dissolved minerals that will cause scaling in the CPAP reservoir.
Similarly, water that has been run through a home filtration system, such as a carbon filter, only removes certain taste and odor contaminants. These filters do not remove the majority of dissolved inorganic minerals, nor do they guarantee the elimination of all pathogens. Therefore, they still carry the risks of both machine damage and potential respiratory irritation.