Mm, that's gonna be a problem if you're gonna travel up to Violet. There isn't a lot of water on the way. [stroking the hypothetical beard while thinking. hold on. this might take a while.]

Teaching it to Surf might be good, but you can't use that outside of battles yet. I guess if you can find a cart with a tank that can store water enough for the Lapras and get a Pokemon strong enough to carry it around, that could work.

...Or you could just tell it to bear with the 'ball for a few more days until you get to Violet.