Here we use Beechnut Nursey Water to mix formula. We buy it by the gallon and leave it on the counter to always serve at room temperature. It is purified and has flouride. Since it is the same or cheaper than regular bottled water, and available at the grocery store, it makes sense.
I'll take your advice and switch to regular old bottled water for the week, but can't bring myself to use the tap! I have done it in a pinch, but since its out of state for us, I don't want to mess with baby's delicate stomach!
Thanks so much!