I usually use filtered water from the fridge, but when I don't have that available, I would use bottled spring water, distilled, a combination of the two, etc; I was on the move a lot with the Navy so my water sources were varied. There were times I wasn't able to keep my fermentation temps cool enough but even on batches where I felt like everything went well, I still had a strange flavor. A couple brewers have told me that they think it is just because of using extract. That's why I'm hoping to learn more about how to treat water to get it just right for all grain. I have a lot to learn...