I'm more concerned that he's not peeing enough!! Is he drinking well?? At 5 months old he should already have a regular potty schedule established. I would first called the breeder and explain the problem to her/him and ask if the pup had been potty trained, if he had ever exhibited this type of behavior before, etc. Did you see his housing at the breeders? I'm wondering if he was kept crated and left to eliminate in his "house," not knowing what it means to be taken out to pee. I would then call the vet to have him checked to make sure there is nothing physically wrong with him. He might have an infection. Has he had his first visit to the vets' yet? You should take him for a well doggie check up, regardless. Congratulations on your new addition. What's his name?? Try not to worry. He's probably just getting adjusted to his new surroundings and schedule! Let us know how it goes!