Hi just seeing this..how is your baby? My Biewer did the same thing when I first got him..I never saw a dog pee so much.
He drank so much water but it was only during the day. He was holding it at night so that told me to bladder infection. We still took him to the vet and he said the protein in the food we were feeding him was way too high which in turn makes them drink more water, which in turn makes them pee more..lol. He was on a 40%+ protein (NV Instinct) so we switched him to the NV Prairie which is around 23%. Our vet said to stick between the 20-30% range and once we switched we saw the problem decrease a lot.
Let us know how it's going.