11yo drinking way too much water - thyroid or kidneys?

I noticed she is drinking the water bowl empty twice a day and her urine is getting lighter in color. She is 11 years old. I am worried this is either hyperthyroidism or early kidney issues. I usually wait for a consensus before changing her routine, but I am not sure which test to ask for first. Has anyone else seen this pattern?

This is a very common question. I would suggest looking at T4 or Creatinine first? which breaks down the diagnostic priority. In my experience with Nala, kidney issues often present with weight loss and vomiting, while thyroid issues can look like just increased thirst and hunger. Check Hyperthyroidism signs I missed for a list of subtle symptoms you might have overlooked.

My Lady is 9 and has kidney issues. See Lady's kidney numbers trending up for how her bloodwork looked. I think you should get both tested. It is hard to tell the difference without labs. I am anxious about missing early signs. Also, have you tried the hydration tips in Getting Nala to drink more? Sometimes just adding water to food helps.

Stop guessing. Get the bloodwork done. I don't care if it is thyroid or kidneys, you need numbers. I had my vet check Rocky's thyroid when he was 10 just to be safe. It cost a few bucks but gave me peace of mind. If it is kidneys, you need to start managing it now. Don't wait for consensus.

Thank you all. I will call the vet tomorrow to schedule a full panel. I think I will do the T4 and creatinine together. I am glad I found this thread.