Yup. Empty water forces your body to use it's mineral reserves. Coffee, alcohol, and processed food, too.
My mom had the same issue; this permanently resolved it. She thought it was old age.
I'll save you some time. Here's what I use after years of evaluating different products.
Mag glycinate:
https://www.amazon.com/dp/B0058HWV9S
Mag chloride spray:
https://www.amazon.com/Ancient-Minerals-Magnesium-Ultra-OptiMSM/dp/B008JSJ9HU/
Ioic minerals (for your water):
Discussion
No coffee, haven't had a drink for over a week, and try not to have too many processed foods...
Then it must be:
A. Filtered water stealing your minerals.
B. Most of our food supply has lost most of it's mineral content over the decades due to monocropping and soil debasement.
You're using your reserves and they aren't being replenished through the ordinary means.
I recommend everyone take minerals because of this problem.