Tap water is fine to use in a humidifier, but if you want to avoid the descaling routine below, consider filling the tank with distilled water. Distilled water doesn’t contain minerals, so it won’t leave any residue on the sides or bottom of the humidifier. To disinfect the machine, let a solution of water and a small amount of bleach sit in the tank for 20 minutes, then rinse the machine until the smell of bleach is completely gone. Viola—your humidifier is now germ-free.
