Would it make sense to harvest asteroids for water and bring it to the moon?

I am thinking about just one spaceship which could go back and forth between some asteroid and a moon orbit. It shoots the water down to the moon, so that it does not even have to touch-down and take-off again. How much energy would be needed for such a mission? Probably it would be a very complex mission to get right, but once it is established you might have water for free on the moon.