Act One: The inside of the tank starts looking like a cave with stalactites—hard, crusty mineral deposits. Act Two: The machine starts making a noise like a dying robot because the internal parts are caked in gunk. Act Three: It just stops working. You shake it, you plead, but it’s dead. Tap water killed it.
Moral of the story: tap water is the candy of humidifiers. A little bit won’t kill you, but a steady diet will cause a lot of problems. Stick to the boring, pure stuff for a long, happy life.
The Do’s and Don’ts of Using Tap Water in Your Humidifier – Plentiful Air