Some puppies get so excited when someone comes through the door that they urinate on the floor. Even a well trained, older dog can exhibit this behavior.  When a puppy gets older and gets a little more confident, accidental urination should go away.  The dog owner can re-enforce this behavior by accident.  If your dog is having accidents when you walk through the door and medical conditions were ruled out by your veterinarian,  never scold your puppy for this behavior and don’t reward him for it either. Hold off on any dog treats until later.   If you console the dog after he pees on the floor, you are sending the message that this behavior is OK.  Always keep your entrance to the house low key. Ignore the dogs excitement and wait until he is calm before you pet him.