Vienna's mountain-spring-fed tap water is completely safe and a pleasure to drink.
Comprehensive travel insurance to cover any medical problems is strongly recommended.
Citizens of the EU, Switzerland, Iceland, Norway and Liechtenstein receive free or reduced-cost, state-provided, health-care cover with the European Health Insurance Card (EHIC; called the ecard in Austria, EKVK in German). If you qualify, make sure you arrange it in your home country prior to travelling to Austria.
No vaccinations are required when travelling to Austria, but the World Health Organization (WHO) recommends that all travellers be covered for diphtheria, tetanus, measles, mumps, rubella and polio, regardless of their destination.