IN my case i noticed antibioitcs in the past have corrected this issue so id link it to bacterial/candida related cause in either/and the kidneys/colon.
these thing can cause chronic dehydration that all the water in the world probably wont fix.
probiotics can also help hydrate but i need a huge amount to do it and it doesnt seem to build up in my system.
I also think i have a leaky gut so take that for what its worth.