Let's be honest, unless you're traveling to regions where drinking tap water would mean an almost certain trip to the hospital, you have no reason not to bring your own water bottle. Most countries in Europe have excellent tap water – especially countries in the Alps – so filling up a reusable bottle will not only save you money but also reduce your waste footprint. I swear by Hydro Flask bottles because once you realize you can have cold water all day, other bottles just don't cut it. They're durable, easy to clean, sleek looking, and come in a variety of colors and sizes to fit your needs.