> does anyone know the reason that use of distilled water is
> recommended for the humidifier?
Multiple reasons. 1) What ozij said. Mineral deposits. 2) Stuff grows in tap water. Google "coliform" and [your local water district].
In Marin county in CA, 2.7 _million_ gallons of treated and untreated sewage was recently spilled into the bay. Some local water districts get their water from the bay.
This is from state.ky.us:
"The presence of fecal coliform bacteria in aquatic environments indicates that the water has been contaminated with the fecal material of man or other animals. At the time this occurred, the source water may have been contaminated by pathogens or disease producing bacteria or viruses which can also exist in fecal material. Some waterborne pathogenic diseases include typhoid fever, viral and bacterial gastroenteritis and hepatitis A. The presence of fecal contamination is an indicator that a potential health risk exists for individuals exposed to this water. Fecal coliform bacteria may occur in ambient water as a result of the overflow of domestic sewage or nonpoint sources of human and animal waste." Then they call it "relatively harmless microorganisms". _That's_ bureaucrat-speak for you!
When it goes through a water treatment plant virtually all, but not 100%, is removed.
Bottom line: this is a _10 cent per night_ decision, based on the price of distilled water at most stores. No good reason not to use it. Some might say "Well, you have to buy it." But most people I know occasionally go to the store anyway.
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