According to the British tourism-info website Justtheflight, the Croatian tap water is not suitable for drinking. Interestingly, most of the eastern Europe is in the red (not-drinkable water) zone and so is the South America, almost whole Asia and complete Africa. The blue zones (drinkable water) are in North America, Australia and New Zeland, the whole western Europe, Japan, South Korea and Singapour.
(pictures: justtheflight)
How about you? Do you drink tap water in Croatia? What is your experience?