It is much easier if you drain it, but it isn't completely necessary. I have one of these in my backyard and I have never drained it, and have moved it several times. However, it is recommended that you drain it when you move it. If you are simply moving it a foot or 2 away, then you can lean it one way or the other and roll the base into place. If you are moving it far distances, then I would recommend draining it.