Continuous Positive Airway Pressure (CPAP) therapy is a common and effective treatment for individuals diagnosed with obstructive sleep apnea. This machine works by delivering a stream of pressurized air through a hose and mask to keep the user’s upper airway open during sleep. Many CPAP devices include a humidifier component, which is a small, removable water chamber designed to add moisture to the pressurized air stream. The primary function of this component is to increase user comfort by mitigating the drying effects of the air.
The Purpose of CPAP Humidifier Water
The constant flow of air delivered by a CPAP machine can be quite dry, causing discomfort such as nasal congestion, dryness, and a sore throat. The humidifier is designed to counteract these side effects. This small water chamber contains a heated plate that warms the water, converting it into an invisible vapor.
This warm, moist air is then carried through the tubing and into the mask, mimicking the natural humidification process that normally occurs in the nose and sinuses. By adding moisture, the humidifier helps to keep the mucous membranes hydrated, promoting better respiratory health and overall comfort throughout the night. Improved comfort with the machine often leads to consistent nightly use, which is necessary for effective therapy.
The Health and Safety of Drinking Reservoir Water
The water remaining in a CPAP reservoir after use is not safe to drink. Even if the water was clean when poured in, the reservoir environment quickly becomes a breeding ground for various microorganisms. The combination of warmth from the heated plate, darkness, and moisture creates an ideal habitat for the rapid growth of bacteria, mold, and biofilm.
Biofilm is a slimy layer of microorganisms that adheres to the surfaces of the water chamber. Ingesting this stagnant, contaminated water can introduce pathogens directly into the digestive system, potentially leading to gastrointestinal distress, nausea, or vomiting. Furthermore, the primary risk of this contamination is through inhalation, not ingestion, as the machine aerosolizes the water and any microbes it contains.
Microorganisms such as Pseudomonas aeruginosa and Legionella spp. can thrive in this environment, and breathing them in can lead to respiratory tract infections, particularly for individuals with compromised immune systems. While your stomach acid may neutralize many pathogens found in drinking water, the respiratory system lacks this defense, making the inhalation of contaminated mist a serious health concern. Therefore, the water in a used CPAP reservoir is never suitable for consumption.
Why Distilled Water is Mandatory for CPAP Use
The requirement for distilled water is fundamentally about machine longevity. Tap water and most bottled waters contain various minerals, such as calcium, magnesium, and iron, referred to as total dissolved solids (TDS). When the CPAP humidifier heats the water, only the pure water vaporizes, leaving these minerals behind in the chamber.
Over time, this process results in a hard, crusty residue known as scaling or mineral buildup on the heating plate and the walls of the reservoir. This scaling reduces the efficiency of the machine, can lead to poor humidification, and may eventually damage the device, possibly voiding the manufacturer’s warranty. Distilled water is created through vaporization and condensation, removing virtually all minerals and impurities.
Using distilled water ensures that no mineral deposits form, keeping the machine operating effectively for its intended lifespan. Additionally, using tap water can cause chemicals like chlorine, often added to municipal water supplies, to be released into the air you breathe. While distilled water is generally safe to drink, it is not recommended for regular consumption because the distillation process removes all naturally occurring electrolytes.
Preventing Contamination and Accidental Ingestion
Maintaining a rigorous cleaning schedule is necessary to prevent microbial contamination and the formation of biofilm in the CPAP components. The water chamber should be emptied every morning, and any remaining water must be discarded immediately. Allowing water to sit in the reservoir throughout the day encourages bacterial growth.
Daily Cleaning
The water chamber should be washed daily using warm water and a mild, unscented soap, then thoroughly rinsed and allowed to air dry completely.
Weekly Sanitization
Once a week, a deeper sanitizing clean is recommended, often involving soaking the chamber in a solution of one part white vinegar to three parts water for about 30 minutes. To avoid accidental ingestion, always dispose of the water down a sink or drain, keeping the reservoir separate from drinking containers or kitchen glassware.