No vaccinations are required for travel to Berlin, but the World Health Organization (WHO) recommends that all travellers be covered for diphtheria, tetanus, measles, mumps, rubella and polio.
If you are a citizen of the EU, the European Health Insurance Card (EHIC) entitles you to reduced-cost or free medical treatment for illness or injury, but not emergency repatriation home. Check with your local health authorities for information on how to obtain an EHIC. Non-EU citizens should check if a similar reciprocal agreement exists between their country and Germany, or if their policy at home provides worldwide healthcare coverage.
If you need to buy travel health insurance, be sure to get a policy that also covers emergency repatriation. While some plans pay doctors or hospitals directly, note that many healthcare providers may still demand immediate payment from nonlocals. Most do not accept credit cards.
Tap water is perfectly fine to drink, although most people prefer bottled sparkling or still water. It is not customary to receive a glass of tap water in cafes or restaurants and asking for one may be met with the suggestion that you order the bottled variety.