If you use a Continuous Positive Airway Pressure (CPAP) machine, you are likely familiar with its built-in humidifier, which adds moisture to the pressurized air to prevent dryness and irritation in the airways. The standard recommendation for this reservoir is distilled water, but running out can happen unexpectedly, especially during travel. While distilled water remains the best option, safe, temporary alternatives exist to ensure your therapy continues without interruption. The priority is protecting both your respiratory health and the longevity of your machine until you can acquire a fresh supply.
The Necessity of Water Purity in CPAP Humidifiers
Distilled water is the industry standard because it is nearly pure H2O, free of minerals and most contaminants. This purity is extremely important for both the mechanics of the CPAP device and the user’s health. Non-distilled water, such as tap or spring water, contains dissolved minerals like calcium, magnesium, and iron, which are harmless when swallowed but problematic when aerosolized and heated.
When the water in the humidifier chamber evaporates, these minerals are left behind, forming a hard, crusty residue known as scaling. This buildup accumulates on the heating plate and the walls of the water tank, reducing the machine’s efficiency and potentially causing clogs or malfunctions. Mineral deposits can also void the manufacturer’s warranty and shorten the overall lifespan of the humidifier component.
Using unpurified water introduces potential health risks because the CPAP machine bypasses the body’s natural defense mechanisms. While stomach acid can neutralize microorganisms in drinking water, the respiratory system lacks this protection. Tap water can harbor bacteria, fungi, or pathogens, such as Legionella or Pseudomonas aeruginosa, which, when inhaled as a fine mist, can lead to respiratory infections.
Safe Temporary Water Alternatives
If your supply of distilled water is exhausted, the safest temporary alternative is sterile water, often sold in small bottles labeled for inhalation or irrigation. Sterile water is designed to be free of microorganisms and is a suitable short-term replacement because it does not carry the same pathogen risk as tap water. This option is commonly found at pharmacies and is ideal for a night or two of use.
A last-resort option is using tap water that has been sterilized by boiling. To prepare this, bring tap water to a full, rolling boil for at least one minute, or five minutes if you are at an altitude above 6,500 feet. The boiling process effectively kills most microorganisms, but it does not remove the dissolved minerals.
Once boiled, the water must be allowed to cool completely to room temperature before being poured into the CPAP reservoir, as hot water can damage the tank. Because the minerals remain, using boiled water will still cause scaling and necessitates thorough daily cleaning of the water chamber to prevent excessive residue buildup. This method should only be employed for a maximum of one or two nights until distilled water can be obtained.
Never use regular tap water without boiling it first, as it poses significant risks. Strictly avoid spring water, mineral water, or purified water that has not undergone distillation, as they all contain mineral content that will damage the machine. Furthermore, never add fragrances, essential oils, or chemical solutions to the reservoir. These substances can damage the equipment, compromise the air seal, or directly irritate the lungs when inhaled.
Strategies for Reliable Distilled Water Sourcing
Establishing a reliable sourcing strategy for distilled water is the most effective long-term solution to prevent future shortages. Distilled water is widely available and can be purchased at most major grocery stores, pharmacies, and even home improvement stores. It is usually sold in gallon jugs and is typically located near the bottled drinking water or in the automotive section.
It is helpful to purchase distilled water in bulk to create a buffer supply at home. This reserve should be stored in a cool, dark place to maintain its quality and prevent accidental contamination. Always check the label to ensure the product is marked as “distilled” and not “purified,” “filtered,” or “spring” water, which still contain minerals.
For travel, a contingency plan can eliminate the need for emergency alternatives. Keep a small, sealed bottle of sterile water designated for your CPAP travel kit. If you are flying, the Transportation Security Administration (TSA) permits carrying medically necessary water, including distilled water, in quantities greater than the standard 3.4 ounces, but it must be declared at the security checkpoint.