I know this post is actually a day late...but better late than never!
Almost every quilter I know has had issues with their irons. I think the most common one I hear about is irons spitting. I had a wonderful Rowenta iron that I absolutely loved, then I moved to a town where the town water was very hard (lots of mineral deposits on things) and it a manner of months, my iron was toast.
Even if I tried to put filtered or distilled water into it afterwards, it still didn't work properly. I miss my iron! :-(
I now use only distilled water in my iron. Some manuals for irons say not to use filtered water or distilled water, but the distilled water has absolutely nothing in it that will harm the iron. In fact, since I've used distilled water I have NO spitting or leaks from irons. The steam seems to be better, too.
While tap water is "free", distilled water is usually very inexpensive. I can purchase a gallon of distilled water at Walmart for about 50-75 cents. Paying 50-75 cents a gallon for distilled water is worth it to me such that I'm not fighting with the spitting and not having to replace expensive irons.
~Sarah at upstateNYCreations