I have a 2 3/4 year old Shih Tzu female dog. She drinks very little water, and I have to force her to go pee (she will hold it for a long time because when I make her go, she pees a lot then sits down quickly and does a lot of cleaning. I feed her Science Diet Sensitive Skin food (adding salt like my vet recommended to make her drink more) and have just recently taken her off table scraps. To tell you what a smart little one I have, I would take her out every 2-3 hours to make her pee so she wouldn't get stones (also recommended by my vet) and she would squat for about 30 seconds and turn around and come back to me. I would check her, and she would be dry!!! After putting her back on the grass 2 or 3 times, she would finally pee!
What can I do for her?
I am not sure if there is anything wrong with her. maybe she will just urinate when she is ready. (I assume your vet has checked her urine to rule out a Urinary tract infection). In the absence of any medical problems it sounds like this is just the way it is. Good luck, vetcare