Distilled water has, by the process of distilling (turning water into steam and then recondencing it back to water) lost the mineral content. Mineral content is the stuff you see in the bottom of the water receptacle of your coffee maker, and it will also kill your clothing iron (cakes up the insides).
so that is why you use distilled water in making juice. It is kinder to coils/atties and doesn't leave behind mineral residue.
I agree with ^^^^^^ logically.
In practicality, I use tap water and I even have hard water. My rationale: 1) Coils don't last 20 years like irons, 2) I clean em with tap water too and 3) it's far easier and that counts for a lot. I do blow the water out after cleaning though and only use a little in the juice. The other juice ingredients gunk the coil a lot faster.
It depends. If you're trying to keep an atomizer going for 6 months, use only distilled. If you toss it every month or two, use whatever you want. Cartos and such...don't last that long to worry about.
Easy tip: If you only need a few drops of distilled water, collect some on the lid of a pot of boiling water. Easier, since gallons of distilled are only good for a few weeks once opened (bacteria).