The only water that I think is good is reverse osmosis water. The main reason is to remove fluoride which I found is a poison instead of helping our teeth it actually make it worse.

As for alkaline water, it could have some benefit. As I learned from my vegan diet, omnivorous diet is mostly acidic and by changing my diet to vegan, it has become predominantly alkaline. I would not dismiss the akaline water theory blindly but from my understanding, it would have little to no effect on me as my food is already alkaline.