jrod wrote:Will using regular tap water damage my machine or cause ill effects?
If you would be prepared to injest the water (that is, drink it) then its OK to use it in your humidifier.
The instructions that come with xPAP systems in most of the world simply say "clean water" or similar... the fixation on distilled
water in a particularly North American thing. Distilled
water is not generally a supermarket commodity item outside North America, but if you don't want to use the local tap water there are a whole host of bottled "pure" waters that are readily available.
Also, prolonged use of tap water will not harm your machine in any way, as long as way of you follow reasonable and regular cleaning practices (which you should be doing for other reasons anyway)!