19 Week old Pomeranian Puppy peeing every 15 minutes!?

Our puppy is peeing every fifteen minutes! He is a male pomeranian, 19 weeks, doesn't lift his leg when he goes, drinks a lot of water, does not seem to be in pain or discomfort when he pees, very active, pees in the house, puddle are about the size of a sand dollar or sometimes larger. He was eating EVO food but I read that the high protein could be too much for his kidneys so we are in the process of switching him to Solid Gold "Just a Wee Bit." Do you think it was the protein???