Continuous Positive Airway Pressure (CPAP) therapy treats obstructive sleep apnea by delivering pressurized air through a mask to keep the user’s airway open. Many CPAP devices include a heated humidifier to add moisture to the pressurized air, which helps prevent dryness and irritation in the nasal passages and throat. The water in this humidifier is not intended for consumption, and the direct answer to whether you can drink CPAP water is an unequivocal “No.” The risks associated with consuming this water involve both the unsterile nature of the water source and the environment created by the CPAP machine itself.
Why Water in the CPAP Tank is Unsafe for Consumption
The environment inside a CPAP humidifier tank quickly transforms even initially clean water into a potential biological hazard. The reservoir provides a warm, dark, and stagnant setting, which is an ideal breeding ground for various microorganisms. This combination of warmth from the heating element and standing water encourages the rapid proliferation of bacteria, mold, and fungi.
Over time, these microbes can form a complex layer known as a biofilm on the inside surfaces of the water chamber. This slimy matrix protects the organisms from routine cleaning and allows them to multiply undisturbed. Pathogens such as Pseudomonas aeruginosa or Legionella species can colonize the tank.
Even freshly added water becomes contaminated during machine operation. Air drawn into the machine introduces airborne particles, dust, and spores into the water reservoir. Once these contaminants enter the warm, moist tank and are left to sit, the resulting water is biologically unsafe for human ingestion.
The Importance of Using Distilled Water
The standard recommendation is to use only distilled water in a CPAP humidifier, primarily to protect the machine and the user from mineral content. Distilled water is stripped of dissolved solids, minerals, and impurities. Standard tap water contains minerals like calcium, magnesium, and iron, even if it is safe for drinking.
When tap water is heated in the CPAP humidifier, the pure water evaporates, but the mineral content is left behind in the tank. This leads to the formation of hard deposits known as scaling or calcification on the heating element and the reservoir walls. This mineral buildup degrades the machine’s performance, reduces the efficiency of the humidification, and can shorten the lifespan of the device.
Mineral deposits also pose an inhalation risk to the user. Over time, these fine mineral particles can become aerosolized and delivered through the mask directly into the respiratory system. Introducing foreign, non-biological substances into the lungs is a health concern that is entirely avoided by using distilled water.
Health Risks of Ingesting Untreated or Contaminated Water
Drinking the water from a CPAP tank can introduce a high concentration of pathogens directly into the digestive system. While the stomach’s strong acid and the body’s natural defenses can often neutralize many microorganisms, they are not foolproof, and the sheer volume of bacteria or mold could overwhelm them. The most common immediate health risk is acute gastrointestinal distress.
Ingestion of contaminated water can lead to symptoms like nausea, vomiting, abdominal cramping, and diarrhea. These symptoms are caused by bacteria and fungi that have multiplied in the stagnant reservoir and are known to trigger digestive upset. The effects can range from mild discomfort to severe gastroenteritis, depending on the specific pathogen and the user’s immune status.
If tap water was used and consumed, the concentrated mineral salts left behind after evaporation could also contribute to digestive issues. If accidental ingestion occurs and symptoms such as persistent fever, bloody diarrhea, or severe dehydration develop, it is advisable to contact a healthcare professional promptly. These symptoms suggest a more severe infection requiring medical evaluation and possible treatment.