Continuous Positive Airway Pressure (CPAP) therapy treats sleep apnea by delivering pressurized air to keep airways open. Many CPAP machines include a humidifier to add moisture, alleviating side effects like a dry nose or throat. Manufacturers and experts consistently recommend distilled water for its purity, benefiting both machine longevity and user health.
Impact on Your CPAP Machine
Using non-distilled water in a CPAP humidifier impacts the device. Tap water contains minerals like calcium and magnesium. When heated, these minerals do not evaporate with the water vapor but are left behind, forming limescale or white residue. This buildup can accumulate in the humidifier chamber, on the heating plate, and in the tubing.
Over time, limescale hinders humidifier efficiency by coating the heating element, making it less effective at warming and humidifying air. These deposits can also damage machine components, including seals, leading to reduced performance. Extensive mineral buildup may necessitate replacing the humidifier chamber or other parts, shortening your CPAP equipment’s lifespan. Moreover, some tap water may contain additives like chlorine or fluoride, which can further impact the machine’s components.
Potential Health Concerns
Beyond machine maintenance, using non-distilled water in a CPAP humidifier poses health risks. Tap water is not sterile and can contain microorganisms like bacteria, fungi, and protozoa. While generally safe for drinking due to stomach acids neutralizing ingested microorganisms, the respiratory tract lacks this defense. When non-distilled water is heated and aerosolized by the humidifier, these microbes can be inhaled directly into the lungs.
Inhaling these contaminants can lead to respiratory infections, airway irritation, and allergic reactions, especially for those with compromised immune systems. Specific pathogens like Legionella (causing Legionnaires’ disease) and amoebae such as Acanthamoeba and Naegleria fowleri have been linked to severe lung, eye, or brain infections if inhaled. Even if risk varies by local water quality, the direct inhalation route makes distilled water a significant health protection.
What to Do and When It’s Okay
If non-distilled water has been accidentally used, immediate action can mitigate issues. Thoroughly clean the humidifier chamber, tubing, and mask with warm, soapy water. Inspect the chamber for mineral buildup or discoloration; if present, a solution of one part white vinegar to three parts water can remove limescale. Ensure all components are completely dry before reassembly to prevent microbial growth.
In emergencies where distilled water is unavailable, temporary alternatives exist, but are not long-term solutions. Bottled water labeled “purified” may be used, though it can still contain trace minerals causing buildup. Boiling tap water for at least one to five minutes and allowing it to cool can kill most microorganisms, but it will not remove minerals, meaning limescale buildup will still occur. These options are for short-term use only, requiring increased humidifier chamber cleaning. The overall recommendation remains the consistent use of distilled water to maintain both machine integrity and user health.