That's admirable, as untainted water is definitely one of the most beneficial things to drink. But we also don't like to encourage the perpetuation of myths, there's a lot of artificial sweetener smoke, and very little actual fire. Scientifically speaking.
Correct. There is no scientific evidence to suggest that diet sodas has any negative health effects when used in moderation. It's bad for your teeth but it's actually less bad than sugary sodas, and when used in moderation this shouldn't be much of a problem.