demineralized water - not sterile

[awhitlock]

Hello, thank you all in advance for the help.  I've been using my CPAP for about a year now and I travel often for work and take it with me wherever I go.  Normally, I always use distilled water as its easy to come by, no matter where I go in the states.

However, I'm currently in Germany and I can't seem to find it anywhere, but I did get some demineralized water, but the label says its not sterile.  Should I use this stuff as is or skip it until I can find the right stuff?

When I was in Japan, I found some 'nursery water' that seemed like it was close to pure as possible and used it in my machine without any buildup or crud, but when I used some here in Germany, I got tons of it.

Any help you can give would be greatly appreciated.

[Walla Walla]

Distilled and demineralized are the same thing I believe.

[awhitlock]

I'm more worried about the label saying not sterile... 

[Ron AKA]

Let me try and explain it a bit. Demineralized water is technically a general term for water which surprise surprise has had the minerals removed. Other terms are used to describe the method used to remove the minerals. If you boil the water and condense the steam that is called distillation. Your CPAP humidifier is a form of distillation as it evaporates the water and leaves the crud behind, if there is any. The term demineralization is often used to describe water purified by ion exchange kind of like a water softener, but ion exchange to produce true demineralized water removes both the soft and hard minerals to give pure water. It is probably the purest water available. Reverse osmosis is another method used to produce demineralized water. In terms of quality probably ion exchange demineralization is the best, distallation is next, and reverse osmosis depending on the complexity of the equipment used, may be poorer or about equal to distallation. 

All of these methods remove chlorine and as such unless chlorine or ozone is added back in the water can become contaminated. It is probably more of a theoretical problem than a real problem however. If it is water for domestic consumption I think you could be pretty sure it is ok. 

When traveling we look for drinking water that has been purified using reverse osmosis and no minerals have been added back in. Failing that we just use tap water and then vinegar or citric acid to clean out the crud when we get back home. It helps to dump out the unused water each day before you add more, if just using tap water.

[awhitlock]

...

All of these methods remove chlorine and as such unless chlorine or ozone is added back in the water can become contaminated. It is probably more of a theoretical problem than a real problem however. If it is water for domestic consumption I think you could be pretty sure it is ok. 

When traveling we look for drinking water that has been purified using reverse osmosis and no minerals have been added back in. Failing that we just use tap water and then vinegar or citric acid to clean out the crud when we get back home. It helps to dump out the unused water each day before you add more, if just using tap water.

Thank you for the answer - I had an idea that the 'nicht steril' warning on the label might be more of a CYA warning than an actual one, but still made me a bit wary.  I'm going to try it tonight (after I clean my reservoir out) and dump whatever's left when I wake up to keep the tank dry.

[Melman]

Don't worry about the water not being sterile. You don't, and probably never have used sterile water in your CPAP unless you purchase sterile water for injection (also known as sterile water for irrigation) from a pharmacy for $15-20 per liter. Over the counter distilled water and demineralized water are not sterile. Your dehumidifier chamber hose and mask are not sterile. The air you breath is not sterile. If you were to add sterile water to your dehumidifier it would be immediately rendered not sterile due to the exposure to the air and the surfaces of the chamber. It would pick up even more microorganisms from the stream of air passing over it since the inlet filter on your CPAP does not sterilize the air. Bacteria that grow in water will grow just as well in water what is initially sterile as in non-sterile water. It will have a population of harmless bacteria within a few hours.


Any water that is safe to drink is safe for use in your dehumidifier. Sterility is not necessary or even advantageous in any way. The only advantage to demineralized or distilled water is that you are less likely to have to deal with mineral deposits. Many on the forum use tap water.

Actually, the most pure water is produced by a combination of mixed resin ion exchange and/or reverse osmosis, followed by multi-phase
(multi-effect) distillation. That is how USP water for injection is produced for the production of sterile pharmaceuticals. Even after that treatment it is not sterile. It must be sterilized by passage through sterilizing membrane filters or heated to 250 deg F under 15psi pressure.

 A less pure grade of water known as USP purified water is produced by ion exchange treatment or reverse osmosis. The best industrial RO systems will produce water as pure as that produced by ion exchange treatment.

I doubt that the distilled or demineralized water we buy for a dollar or so per gallon meets the requirements foe USP purified water nor does it need to for our use.

[Sleep2Snore]

If it is not sterile and it worries you, buy a kettle and boil it and allow to cool.  Do not use the kettle for anything else.
You can get small kettles for caravans 220vAc for Germany.

[Melman]

Although boiling will kill most bacteria it does not assure sterility and the temperature achieved is altitude dependent. Heating to 250F (121C) for at least 15 min is required to assure sterility. But as I said previously, it is not a concern. Even if you sterilize the water you will still be breathing non-sterile air. We all do.

[jaswilliams]

As long as the demineralised water is Potable ie can be drunk it’s fine. In the UK it’s very hard to by distilled water. And demineralised water is usually for the automotive industry and topping up car batteries, this water is not suitable for drinking. We just use tap water and remove the scale when it forms... or bottled water with a very low mineral content

[SarcasticDave94]

Let me try and explain it a bit. Demineralized water is technically a general term for water which surprise surprise has had the minerals removed. Other terms are used to describe the method used to remove the minerals. If you boil the water and condense the steam that is called distillation. Your CPAP humidifier is a form of distillation as it evaporates the water and leaves the crud behind, if there is any. The term demineralization is often used to describe water purified by ion exchange kind of like a water softener, but ion exchange to produce true demineralized water removes both the soft and hard minerals to give pure water. It is probably the purest water available. Reverse osmosis is another method used to produce demineralized water. In terms of quality probably ion exchange demineralization is the best, distallation is next, and reverse osmosis depending on the complexity of the equipment used, may be poorer or about equal to distallation. 

All of these methods remove chlorine and as such unless chlorine or ozone is added back in the water can become contaminated. It is probably more of a theoretical problem than a real problem however. If it is water for domestic consumption I think you could be pretty sure it is ok. 

When traveling we look for drinking water that has been purified using reverse osmosis and no minerals have been added back in. Failing that we just use tap water and then vinegar or citric acid to clean out the crud when we get back home. It helps to dump out the unused water each day before you add more, if just using tap water.

this has to be one of the best detailed water posts I've read yet. No kidding, great job.