That is still not dehydrated water.

actually no, she's talking dehydrated water as in powdered water (assuming she's talking pure water as well). every sort of deposit we know is a type of salt deposit, meaning it is not dehydrated water.

the reason why the idea is impossible is because dehydrating something means taking the water out of it, so in order to dehydrate water you'd have to take the H20 out of the H20, which would leave you with nothing.

nothing but calcium deposits.
if you just add water to those deposits you have normal tap water.

yes but it's not pure water is it?

100% pure water (or anything, for that matter) is not something that you've seen

further proving that dehydrated water isn't possible.