Wow - I had never heard that about distilled water in irons before either. I have always used distilled water in my iron, thinking that it was the best. If I use tap water or even filtered water around here where I live (which is chock-full of minerals, being "hard water" from our limestone aquifer), the iron will scale up immediately and ruin both my clothes and the iron. I guess I'll start using bottled water that's been through reverse-osmosis, which is better than simply "filtered", but not as harsh as distilled water.

By the way, on that subject, drinking distilled water can be dangerous too. It leeches important minerals and other compounds from your cells. Y'all can Google that subject for more info.