How to create real water?

Hi! I saw that the easyest way to insert water in a scene is to use a water prefab, which by no means is not "real" water, in the sense that it doesn't adapt to the surface and it does not drain if there is a hole in its container, for example. Basically, it is just a plain object with a water animation on it. But what if I'd like to create a lake filled with water? What if I'd like to drain the water from a container? Do I have to use particles? And last question: would "real" water be too much expensive to use with Gear VR? Thanks in advance and have a nice day!