This happened to me while being treated for kidney stones. Doctors kept telling me to drink more water. When they would tell me 4 12 oz glasses of water/day, I told them I drank well over that. After a few months and several emergency or urgent care visits my urologist finally figured out it wasn’t a problem of low water intake but excess intake. Now restricted to 4 qts/day.
Possibly there’s a genetic component as I had an aunt with this problem. It struck her when she was older and she was at death’s door when the hospital figured it out. Because of her experience I was supplementing the super excess of water with minerals and sea salt. I knew their orders of so much water was draining me but because I did pass a couple of kidney stones I was trying to go with the program to flush them out. Since I kept having UTI symptoms (very painful) the general practitioners just thought water was the answer. Took the urologist to recognize the real issue.
Bet part of the problem is city chemically treated water.