Well, that depends on what you mean by finite. If you're talking about making water source blocks not create additional source blocks, that's definitely doable (whether or not you need to make a CoreMod to do so is another story).
If you're referring to Minecraft liquids "flowing" when you place them in the world, that's something else entirely. Remember that those fluids are, in fact, finite. The source block is the only real block of fluid.