as famed dracula knower, draculas can't cross flowing water and depending on the mythos even just straight up still water would cause great harm. however it is correct in stating that dracula can indeed get wet.
Greetings and congratulations to Kenyon's graduating class of 2005. There are these two young draculas swimming along and they happen to meet an older dracula swimming the other way, who nods at them and says "Morning, boys. How's the water?" And the two young draculas swim on for a bit, and then eventually one of them looks over at the other and goes "What the hell is water?"