CPAP Water: Distilled or Tap?

CPAP Water: Distilled or Tap?

September 13, 2023 | |

Key Takeaways

  • Distilled water is the preferred water to use with CPAP equipment to ensure lasting performance. 
  • Water (through the use of a humidifier) adds moisture to CPAP therapy for a more comfortable experience. 
  • Water is also essential in the process of cleaning CPAP products for long-lasting equipment. 

The type of water you use for your CPAP humidifier is important to ensure the long life of your machine. Distilled water is the most preferred by CPAP machine manufacturers. Tap water, while less expensive, can cause harm to your machine over time. Filtered water is another option that is comparable to distilled. Avoid bottled waters labeled as spring or mineral water, as they may leave mineral deposits that can cause harm to your machine.  

Benefits of a CPAP Humidifier

A CPAP humidifier can help moisturize the dry air of your CPAP machine. If you wake up with a sore throat, dry nose, or experience frequent nasal infections from CPAP therapy, a humidifier may be the solution. Many humidifiers can also heat the moist air, providing a soothing, warm airflow that makes CPAP therapy more comfortable.  

Types of CPAP Water

There are many different types of water that CPAP patients can use to fill up their humidifiers and clean their CPAP equipment. However, although some water types are more accessible and acceptable to use cleaning equipment than others, distilled is the preferred type to use for CPAP humidifiers. 

  • Tap: The water a person gets directly from a sink in their home is tap water. It is supplied through pipelines and generally comes from dams or rivers nearby. Tap water is effective for cleaning, gardening, laundry, and other household items, but it is not always suitable for drinking or filling up a CPAP humidifier due to the unfiltered minerals or having old pipelines. 
  • Spring: Spring water comes from natural springs in an underground source. Spring water is not recycled and comes directly from the source, but it is safe to drink. 
  • Purified: Purified water is water that has been mechanically filtered or processed to remove impurities and make it suitable for use.
  • Distilled: Distilled water has minerals and salts removed from it to make it one of the purest forms of water. The distillation process is very thorough to remove unwanted contaminants.

Can You Use Tap Water in a Humidifier?

Most tap water contains minerals which can build up inside your CPAP machine humidifier. The minerals and other chemicals in tap water can eventually clog the humidifier tubing and leave residue inside your water chamber. Many of the more sensitive parts of the humidifier may also be affected with regular use of tap water.  

Can You Use Purified Water in a CPAP Machine?

Purified water is a viable option for CPAP machine humidifiers. Purified water systems like reverse osmosis remove most of the minerals and chemicals that can harm your machine. If you have a home purification system, be sure that you are changing the filters as recommended by the manufacturer to ensure that the contaminants are still being removed. You can also use bottled water labeled as purified if you do not have a home water purification system.  

Can You Use Distilled Water in a Humidifier?

Distilled water is the best choice for CPAP machine humidifiers. The distillation process is the most thorough when it comes to removing unwanted contaminants and minerals from water such as heavy metals, calcium, phosphorus and even bacteria. While distilled water can be more expensive it is worth the investment to ensure your CPAP humidifier continues to perform well for years to come.  

Things to Avoid Related to CPAP & Water

Along with use of your CPAP humidifier, water is also essential for cleaning your CPAP equipment. Here are a few things to consider ensuring healthy cleaning of your CPAP machine.  

Avoid using any strong cleaning agents such as bleach, ammonia, rubbing alcohol or anti-bacterial soaps when cleaning your machine. While it may seem like a good way to sanitize your equipment, these chemicals can leave residue that you may end up breathing during CPAP therapy. Also avoid using any perfumes to make your equipment smell better. These too can end up being inhaled while using your machine.  

You can use any water, including plain tap water for cleaning. Just use dish soap to clean hoses, water chambers and other parts. Be sure to rinse thoroughly and allow equipment to dry completely before use.  

Make Your Own Distilled Water for CPAP

If you find that purchasing distilled water is becoming too costly, you can always make your own for CPAP use. 

  • Add 8 cups of any water, including tap water to a large pot. Place a smaller pot inside the large pot so that it floats on the water.
  • Start the stove at medium-high heat. Try not to boil the water. Instead, get a steady simmer going. The goal is to generate water vapor.
  • Place a lid on the large pot upside-down. This will allow for condensation to form and drip into the smaller pot inside.  Add some ice cubes to the upside-down lid to control the temperature. Replace the ice cubes as they melt. Discard the water in the lid as it accumulates. Be sure to handle the upside-down lid carefully as it is hot.  
  • In about an hour, you will have perfectly distilled water in the smaller pot. Let it cool and use it as needed for your CPAP humidifier.  

What is Mineral Buildup?

All the water in the world contains minerals it has absorbed from the earth. These minerals can accumulate over time in plumbing, hoses and any mechanical system that channels water. The buildup can clog and damage equipment. Distillation and filtration processes help remove these minerals to protect hydration technology, including your CPAP humidifier.  

What Water to Use While Traveling

If you wish to stay CPAP compliant when traveling, you will probably take your CPAP equipment with you on your trip. Many portable CPAP machines may include convenient portable humidifiers or allow for the attachment of a portable humidifier as an accessory. However, be sure to avoid using tap water at your travel destination for CPAP therapy. For convenience, you may be tempted to use tap water just once while traveling as it is readily available in hotel bathroom faucets. But dangerous microbes may be in regional tap water resources that can be unhealthy, especially for breathing. It’s safer to purchase enough distilled water to take with you on your trip or purchase distilled water when you arrive at your destination. 

Water to Avoid Using with CPAP Equipment

Boiling water for CPAP use may kill bacteria but does not remove minerals. In fact, you may intensify the mineral concentration in water during the boiling process. Use distilled or purified water only and enjoy the benefits of your CPAP humidifier.


While water is essential for both humidity and cleaning CPAP products, make sure you are using the preferred kind for the best performance. Additionally, if you need to replace your humidifier chamber, make sure you do that too. The CPAP Shop would be happy to help you if you have any additional questions or concerns. We also can provide product recommendations that wil best suit your needs. Give us a call at 866-414-9700 today!

Chris Vasta

Chris Vasta is the president of The CPAP Shop and an expert in sleep and respiratory therapy. He often provides insights on product design and functionality on various manufacturers’ prototypes and is frequently tapped to provide reviews on new releases.