My kid has never eaten sand from her sand water table. She does, however, love to scoop the sand into the water or, even more messy, onto the ground around the table. That's like her favorite thing to do. I just sweep it up. We keep ours out on the (brick) porch. No big deal. Messy fun is for outside and it's outside
DS never really intentionally ate the sand, but it ends up in his mouth often (he'll put something in the sand and then in his mouth, or just touch his mouth with sandy hands...etc). It's fine.
The sand does get everywhere, but he's played in it almost every day for over 9 months now. Best purchase ever.
My kids all are sand at least a couple of times. It comes out the other side, it won't hurt them, and they only do it a couple of times before they realize it's yucky.
We never had a sand and water table so can't answer the other question.