Distilled water versus boiled tap water

I have read (and even written in the water tank of my ResMed S10), that only distilled water should be used in the humidifier.
What would be the problem of using boiled tap water instead of distilled water?
Thank you all.

You would have nice, sterile mineral buildup instead of no mineral buildup.

armando. ntg wrote:I have read (and even written in the water tank of my ResMed S10), that only distilled water should be used in the humidifier.
What would be the problem of using boiled tap water instead of distilled water?
Thank you all.

Distilled water has (presumably) no impurities. Doesn't leave anything behind to clean.
Boiling tap water would actually concentrate the impurities. It would be evaporating the water and leaving the impurities behind. Exactly the opposite of what you're trying to accomplish. No pathogens are going to get carried out of your heated humidifier tank to you because the water vapor molecules are too small to carry them.


Den

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Boiled tap water is worthless (possibly lots of minerals left behind, depending of course on the source and how long you boil it). Use distilled water and prevent most of the mineral scale and slime problems that can occur. Here's something I wrote not too long ago:

viewtopic.php?f=1&t=108168&p=1031955&hi ... k#p1031955

If your only option is boiled water, go for it. If you are in the US, you only need to boil it if you get well water and even that depends on where you live and the water quality of your well. Otherwise, municipal water is fine from the tap.

What is the result? You get a mineral buildup in your humidifier liftout unit and will have to replace it more often. But, for some people, that is acceptable because they either have no means or some difficulty in getting regular supplies of distilled water. It won't hurt you in any way and won't damage the machine in any way. What happens is that the mineral builds up on the bottom and the water won't heat as well due to the thickened buildup of minerals, reducing your humidification. For awhile, you can just raise the humidity level, but eventually, you may have to replace the liftout unit. The elderly people I see that do this replace their humidifier liftout unit every 2-3 years. If you use distilled water, you may never have to replace your humidifier insert for the life of your unit.

Access or even convenience can also be a determiner. Some people live in rural areas where not all town groceries carry distilled water. Some people just have too much on their plate and this would just be one more thing. Some are just lazy. Some just don't care. All valid. The important thing to know though is that municipal tap water will NOT damage your machine and won't hurt you. The distilled water simply extends the life of the insert. Distilled water is not sterile.

Boiling can make water safe to drink, but distilling it makes it nicer to your tank.

chunkyfrog wrote:Boiling can make water safe to drink, but distilling it makes it nicer to your tank.

Tank.. That was the word I was trying to think of. Liftout unit was the next best thing. Thanks. Just didn't want the OP to think that I was speaking of the humidifier rather than the replaceable tank.

It is not just the tank that is going to get mineral build up. The air blowing through the hose is likely to pull some of the wet through the outlet of your machine as well. Unless you are in the UK or Ireland (where distilled water is made from Leprechaun tears apparently), distilled water is cheep. I spend less that 4 dollars a month to fill my humidifier every day.

Distilled water is available everywhere and costs less than 1$ in most places. A gallon lasts me about 2-3 months depending on local humidity. It costs me less than 2¢ day.

Hi. Thank you all for the kind of answers.
My resistance using distilled water is not so much due to the price, although here in Brazil, where I live, it is not so cheap, but mainly due to the difficulty to buy, since the distilled water is not easily found in any store near home, and purchase over the Internet, which would be great, means that it is much more expensive due to the cost of shipping, which can cost up to five times the value of the product.
In any case, I will look for a solution that is viable and instead use distilled water like everyone else.
Thank you all.

The main idea behind using distilled water is the lack of mineral build up in the water chamber.
Boiling is not going to get rid of the minerals..it's just going to concentrate the minerals more and you will just end up with a yucky looking water chamber sooner than later.
Having the water chamber get yucky looking with mineral build up isn't the end of the world...it's easily cleaned out and removed with a solution of vinegar and water.

If I didn't have easy/cheap access to distilled water I would just use tap water (if it's drinkable it's safe for use in the humidifier) or bottled water and be prepared to maybe have to clean with vinegar every now and then. I would dump the water each morning and let the chamber air dry as this would lessen the speed of the mineral build up.

Thank you, Pugsy.
If the problem is only the appearance of the water tank, I'll seriously consider continue to use boiled tap water, and make periodic cleaning with water and vinegar, or even with a citric acid solution, as is done in espresso coffee machines ( I already wash the tank each morning and let dry completely until night). And why to boil the water? Because tap water here in Rio de Janeiro is not as reliable as well. I have no courage to drink it.
Thank you.

You could make a home still from a kettle and tubing. There are plenty of designs on the internet. Also, you could order a small counter-top water distiller. Once a month, you could make a months supply in a few hours.

ResMed sells two kinds of water tubs for the A10 and S9 machines. The "standard" tank is probably labeled "Distilled Water Only" on the tank somewhere. It's usually part of the mold for the clear plastic and shows up as raised letter. The "cleanable" or "dishwashable" tub isn't labeled that way.

If you use drinking water, be sure to dump the water and rinse the tank every morning. Refill with fresh drinking water before bedtime. The idea is to get rid of all the old water to prevent minerals from building up. If any germs have been growing in the water overnight, it washes some of them out. Check the cleanliness of your tank more frequently.

If you have a mineral buildup, the tanks aren't really all that expensive to replace. Here in the US, you can buy them online.

Many of us are concerned about germs in the water tank. In theory, the water evaporates from the water and leaves any germs behind. I'm not sure this is 100% true, but it does help.

Presumably, if your drinking water has dangerous germs, you're already drinking them and inhaling them isn't too much worse.

One of the advantages of distilled water is that there isn't "germ food" in the water. Tap water has various things in it that can feed germ growth, especially after you've evaporated some of the water away and concentrated the contaminants. Think of it this way: If you keep adding water to the tank and letting it evaporate, you eventually end up with a thick soup of the minerals and other contaminants.

Unless you let it boil for a long time, boiling the tap water isn't going concentrate the minerals that much. If you start out with a liter of water, and boil it for a minute or so, you're still going to have pretty close to a liter of water left.

Boiling the water will kill most of the germs that are in your drinking water, but once you put the water into your tank, airborne germs will fall into the water in your tub. Boiling may also drive off any chlorine that was in the water and it may support more germ growth than before. Personally, I wouldn't boil tap water for CPAP.

Given your circumstances and where you are at and the fact that we don't know just how many little bugs might be in tap water (though I have my doubts as to how well they could hitch a ride on a humidity water vapor but better to be safe than sorry)...I think I would also probably just boil the tap water and be prepared to do extra cleaning with the vinegar.

I got a machine a while back (it was an old machine that was donated) that had a high number of machine hours on it and I don't think the person who used it ever used distilled water. That water chamber was really yucky looking but I used a solution of vinegar on it and it came out looking brand new.
If you are proactive with the cleaning and dump the water each morning (if you can) the extra cleaning work shouldn't be all that much.

How much cleaning is going to depend on how much mineral content the local water has.
If it doesn't have much then boiling isn't likely going to concentrate it all that much.
If it does have a high mineral content (mine here is just awfully high) then just be prepared to use the vinegar a little more often. I have had to use well tap water on occasion where I live. Now it's safe to drink but it really has a high mineral content and I can see a difference in just 3 or 4 days. If I used it all the time I would probably use the vinegar once every week or two.
You will be able to tell...it's pretty easy to see.

While distilled is the "ideal" ...sometimes life doesn't give us "ideal" and we have to make do with what we have.