sry i didnt say what a "fan type" was talking about. it has a 2 1/2 gal tank which sits on a base which holds water. on the one side on the base there is a filter type deal that sucks up water. on top of this a fan which pulls air through/around the filter thus making water evaporate.
heres a small pic of one like mine
its the small round pic with "cool mist" by it
i believe unpurified water is safe