Distilled Water

I didn’t notice until I looked in the cabinet that I am out of distilled water. I ran to the only store in our small town and they are out. Everything else within a 20 mile radius is closing at 10. So what do I do? How bad will I hurt my machine if I use tap water for one night?

Hi Mary, there are two reasons I can think of that it’s important to use distilled water in your CPAP (though I’m not a doctor, nor do I have any special knowledge or training in CPAP):

  1. Risk of infection.

There’s all kinds of stuff swimming around inside ordinary water and some of it could be dangerous to breathe in. I believe this is an extremely low risk and I’m not sure there’s ever been a case of someone getting seriously ill from this, but it’s not entirely out of the question. If you don’t have any distilled water around, you can always boil some water to use in your CPAP (of course, let it cool before adding it to your machine). I’ve used ordinary tap water a number of times without incident and I don’t lose sleep (figurative or literal) over it.

  1. Contamination of the CPAP machine

This is the main reason to use distilled water. The minerals in ordinary water can accumulate in your CPAP machine over time and interfere with its operation. However, this is a problem over a long period of time. I’ve used tap water in my machine probably a hundred times over the 5+ years I’ve been on CPAP and it’s still running fine. So I wouldn’t worry too much about it if you’re using distilled water 90% of the time or more.

You can distill water yourself if you really want to. Google can provide you instructions, it’s not difficult but it’s kind of a pain in the rear!

Hope this is helpful.


Thanks Jim. I had to go for it. I could tell the difference. I have been paping for a year and a half and this is the first time I ran out of water. I live in a very small town. We have a Dollar General and that’s it. The next closest store is 15 miles away. I opened the cabinet and thought no big deal, I will just run to the Dollar Store and pick some up. Not a bottle in sight. By then I didn’t have time to get to the other stores because they were closing in 10 minutes. I read and read and the one thing that bothered me was what you said about infection. When the article said you breath the chemicals in the water into your lungs, I almost decided to sit up all night. But I had no choice and did it. Put the tube and chamber in vinegar water as soon as I woke up, then ran to the store and got my 8 gallons on water. I cleaned it all up, Ran some distilled water into the machine and everything seems fine. I just know that I won’t do it again. I was a nervous wreck

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Hi Mary, I’ve been on a bipap for two years and traveled regularly pre-covid. For a week at a time 5x per year I use bottled water and have had no problems.

Good advice listed here but in a pinch fill it and hope it doesn’t dry out. It’s the minerals in the water that does the damage. Clean it out with warm soapy water the next day and get the distilled water asap. I know that Amazon carries it.

Glad to hear it worked out. I think you’re probably overly concerned about the infection risk. I’m sure you were in more danger driving to Dollar General than you are from using tap water. I wouldn’t make a habit of it, but I don’t think you need to worry if it’s only occasional. :grin:

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I did it. I woke up about 4 in the morning and I was almost out of water so I filled it back up. I cleaned it all up the next morning and ran and got the distilled water. We have a Walmart and a Kroger but they are about 20 miles from here and major construction is on the way so part is one lane. It’s just a pain getting there right now. Thanks for the response, I appreciate it.

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One more question… I go through a whole chamber of water a night. I have a Dreamstation BiPap and the DME set the humidification to fixed. I saw the setting and noticed there is an adaptive setting. It sounds like the setting I need based on what I read. Anybody have any input on fixed vs adaptive humidification setting?

Based on my personal experience, using tap water in a CPAP machine for a couple of days will do no harm. Distilled is best, bottled water next, and tap water last. If using other than distilled water, carefully clean the chamber in the morning and you will be goods to go.

I have a Dreamstation ASV machine (a very specialized Bi-level CPAP) and use about 1.5 tanks of water each night. To get to that, I have installed an additional stand a lone humidifier in line with the Dreamstation that provides the extra water. Even so, if I sleep more than 9 hours, both will be completely dry.


The setup is a little different but not too complicated - and it solves the humidity problem.

That’s the one I have. I also go through a lot of water at night and I usually have to get up about 3 in the morning and fill the chamber then it is bone dry in the morning. It drives me nuts and gives me a horrible headache and sore throat. Sounds like you have figured out a work around on the water.

My system consists of the Dreamstation machine. Connected to that is an Fisher-Paykel HC-150 external humidifier using a Roscoe Medical Easy-Flex Lightweight CPAP Hose - 18 Inches long between them then a Hybernite heated rainout control hose connected to my CPAP mask. All the hoses are covered with insulating tubes to help control condensation from the high humidity levels in my system. I made my own from fleece fabric although Philips makes one and there are other third parties that make them as well.

Note that the heated hose that comes with the Dreamstation no longer works because the electrical connection on that hose no longer can be connected to the Dreamstation.

Hi Mary, One thing I have recently done is buy a MegaHome Distiller. It is a little expensive but it works extremely well. It takes about 5.5 hours to do one gallon, but it lists out on the TDS meter (Total Dissolved Solids) as a 6 - practically perfect (and that is our unfiltered tap water - the RO filter lists out as a 1 :slight_smile:) Not helpful now, but maybe in the future. You could also try a zerowater filter and pitcher for your CPAP… Best of luck!

Dreamstation ASV machine is a good one.

I didn’t even think about it but I have to have oxygen with my BiPap and I have an oxygen concentrator that had a water bottle with it until I put it in my additional supplies because I didn’t need it with my humidifier. Should be easy enough to hook it up. Thanks

That should help somewhat depending on how much humidity you need.

One thing to be careful of is the condensation of water in the O2 tube. You can get an Inline Water Trap that is inserted into the oxygen line between the concentrator and the connection to your CPAP. It should hang vertically so the condensate collects in it. They are really inexpensive and your DME (for your concentrator) should have them.

Have you ever thought about becoming an AWAKE Peer Mentor? https://www.sleepapnea.org/peer-mentors/join-asaa/