My dog has a pooping problem. He is a chihuahua about 2 years old and recently had a bad habit. His been pooping in one area of the house. He is trained to do his duties outside, but recently he is pooping just in this one area of the house. I was wondering how can i fix this problem. Maybe a doggy door...

I just wanted to say that the above suggestions are all excellent, and many of them were things I would not have thought of regarding a bathroom. Just proves how valuable these forums can be to all dog owners. Great!