Huh... 🤔 I suppose the aversion to running water should be applicable to pretty much all heavily western yōkai. 'Cause running water in practice is cleaner since it's not stagnant, it is a symbol of purity, and thus a holy barrier to diseases and nasty stuff.

That is to say, it's really nothing specific to vampires. Like garlic. But then again, it's all about common belief – and vampires get a lot of powers and a lot of weaknesses...