Talk to your drs. about water. My dr. gave our healthy baby the water OK at 6 months--tap, bottled, etc. I'm still using Nursery Water but figure after Disney, I may stop. I would avoid Dasani, they add sodium (so you get more thirsty...).
And forget sterile, you just make do. We did a hotel stay in March at 3 months. I took a small amount of dishsoap (in an old travel size shampoo bottle I cleaned). We had two sinks. I washed in warm, soapy in one sink and rinsed cool in the other. Another idea....disposable bottles. We use Avent bottles. I took enough nipples for one day (and probably one extra) and plenty of liners. I think I took one regular bottle. I marked one ziploc as Clean the other as Dirty on masking tape. When we had a chance, we would do a change over and get the water poured for the next bottle. We did buy nursery water then and carried a workout-type bottle with us that had ounce measurements on them. We would take a day's worth of water (we were in and near NYC). Then just added formula when it was time. I plan on doing the same when we go in Aug (then almost 8 months). We are renting a car so we will be making a grocery store/Target run. And I may just use regular bottles of water.
Garden Grocer doesn't seem to carry our formula....the basic Similac milk-based for 0-12 months. At least not on their website. Go figure.