How are you treating him? I have the impression that diet management alone may be all that's needed if the condition is caught early.
We have the same issue with one of our greys, age 5. For months he consumed lots more water than the other dog, was peeing a lot, and sometimes had leakage. He also doesn't have much stamina for walking and overheats easily. It has taken a year for his lab tests to show all the abnormalities of kidney disease, though. (His creatinine has always been a little high, but the vet said that's not necessarily abnormal for greyhounds. Now the BUN and specific gravity are beginning to be wonky too.)
We'll do a complete blood chemistry tomorrow, paying special attention to his phosphorus level. He's not going to do well with a veterinary kidney diet because he doesn't digest grains well. So I'd rather keep him on the food he does well on, found through lengthy trial and error, and just use a phosphorus binder if appropriate.
I don't mean to hijack this thread, but I thought your reply might be of interest to others, while we're on the subject.
Mary