Jun 22nd 2026
Can You Use Purified Water in a CPAP Machine? Distilled vs Purified
Can You Use Purified Water in a CPAP Machine?
Your #1 Choice Should Be Distilled Water. You cannot use purified water in a CPAP Machine. CPAP manufacturers recommend using distilled water because it is pure water with all minerals removed. While purified water has been filtered and is safe to drink, it can still contain trace minerals that may build up inside your CPAP humidifier over time and potentially affect machine performance.
What's the Difference Between Distilled and Purified Water?
Distilled Water Explained
Distilled water goes through a distillation process that removes minerals, inorganic compounds, and microorganisms. As a result, only pure water remains.
Some substances removed during distillation include:
- Bacteria
- Calcium
- Heavy metals
- Magnesium
- Potassium
Because distilled water contains no dissolved minerals, it is the preferred choice for CPAP therapy.
Purified Water Explained
Purified water goes through a purification process, often reverse osmosis, that removes many contaminants and makes the water safe to drink. However, unlike distilled water, purified water may still contain small amounts of minerals.
Although purified water is cleaner than tap water, those remaining minerals can eventually lead to buildup inside your CPAP humidifier.
Side-by-Side Comparison
|
Distilled Water |
Purified Water |
|
Minerals removed through distillation |
Filtered through purification processes |
|
Contains virtually no minerals |
May contain trace minerals |
|
Recommended for daily CPAP use |
Suitable only for occasional emergency use |
|
Helps prevent mineral buildup |
Can contribute to mineral deposits over time |
Why Distilled Water Is Recommended for CPAP
Mineral Buildup and Humidifier Damage
Distilled water is the recommended choice by CPAP manufacturers such because it helps extend the life of your machine and prevent mineral buildup.
Mineral buildup occurs when water containing dissolved minerals evaporates and leaves deposits behind. Over time, these deposits can prevent the humidifier's heating plate from properly warming the water. When this happens, the humidifier may not provide enough moisture, potentially causing dryness or congestion during sleep therapy.
Bacteria and Long-Term Cleanliness
Because distilled water removes minerals, microorganisms, and other impurities, it helps keep the humidifier chamber cleaner over time. Using water sources that contain minerals or contaminants may require more frequent cleaning and maintenance.
What Water Is Safe for a CPAP Machine?
Distilled Water (Best Choice)
Distilled water is the best and most widely recommended option for CPAP machines. It contains no dissolved minerals and helps prevent buildup inside the humidifier chamber and heating system.
Sterile Water (Hospital Use)
Sterile water may also be used in medical settings. However, distilled water remains the most practical and commonly recommended choice for home CPAP users.
Tap, Bottled, Spring, or Filtered Water & Why They're a Bad Idea
Several types of water are safe to drink but not ideal for CPAP machines:
Tap Water – Mineral content varies by location, making it difficult to know what deposits may form inside your humidifier.
Bottled Water – Often contains trace amounts of minerals that can contribute to buildup.
Purified Water – Contains fewer impurities than tap water but may still leave behind minerals.
Boiled Water – Boiling kills bacteria but does not remove minerals.
Spring Water – Naturally contains minerals that can accumulate inside the humidifier chamber.
What can I use if I run out of distilled water?
Short-Term Emergency Options
If you don't have access to distilled water, purified water can be used temporarily in a pinch. However, it should only be used once or twice when no better option is available.
If you use purified water:
- Fill the water tank with enough water for the entire night so it does not run dry.
- Empty the water tank immediately after use.
- Rinse the chamber thoroughly.
- Allow it to air dry.
- Inspect the chamber for any signs of sediment or residue.
- Clean the chamber with mild soap if buildup is present.
Ongoing use of purified water can lead to mineral buildup that may affect your machine and therapy performance.
How to Make Distilled Water at Home
If distilled water is unavailable, you can make it at home using a simple distillation process. Water is boiled, the steam is captured, and then condensed back into liquid form. This process removes minerals and many impurities that remain after boiling alone.
Traveling With Your CPAP: Water Tips
TSA Rules on Distilled Water
When traveling by air, check current TSA guidelines before departure.
A common guideline is that passengers may carry limited amounts of distilled water in carry-on luggage while larger quantities should be packed in checked baggage when permitted. Because regulations can change, always verify current requirements before your trip.
On Cruises and in Hotels
To avoid running out of distilled water while traveling:
- Determine how much water you'll need based on your destination and humidity settings.
- Consider whether you'll be traveling in a dry or humid climate.
- Purchase distilled water before your trip.
- Have distilled water shipped to your hotel or cruise destination when possible.
- Contact your hotel or cruise line in advance to ask whether distilled water can be provided.
FAQs
What happens if I use tap water in my CPAP?
Tap water often contains minerals that can accumulate inside the humidifier chamber and heating plate. Over time, this buildup may reduce performance and increase cleaning requirements.
Can I use purified water once in an emergency?
Yes. Purified water can be used temporarily if distilled water is unavailable. However, it should not become your regular water source because trace minerals may still be present.
Is bottled spring water safe for CPAP?
A popular question from CPAP users is; can you use bottled water in CPAP machine? Spring water is generally not recommended because it naturally contains minerals that can leave deposits inside your CPAP humidifier.
Does the type of water affect CPAP humidifier life?
Yes. Water for CPAP machine containing minerals can lead to buildup inside the humidifier chamber and heating system. Using distilled water for CPAP humidifier helps reduce deposits and may help extend the life of your CPAP equipment.
For additional tips, read How to Travel with a CPAP Machine.
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