Dog owners help shed some light

I work as a nanny taking care of 1 child and the family has a dog. However it's probably the most disgusting dog I came across. He's house trained an pees/poop in the bathroom but after he's done doing that he comes out and drag his shitty butt all over the floor an babymat in order to clean it. Yes u can see the shit marks. The owners completely over look this. Plus he scratches himself right where the baby stuff is. He doesn't get regular shower at all, he only gets groomed once every couple of months. I love dogs/pets but after seeing what this one does I would find it hard to get my own. Please if ur'e a pet owner shed some light. Are all dogs this disgusting? Are you suppose to wipe or wash their butt after they shit etc. How often do are they suppose to get a bath/shower?

update: thanks everyone for your feedback