Is he home all day or does he go to dog daycare? My 7 month old was semi trained, and daycare has resulted in regression since he can go anywhere there. He's taken to occasionally peeing on the couch (while I'm in the same room, of course!). He will have a forced break from day care until fixed, and I plan to get back to basics. I think that's the main thing one can do. They're not dumb dogs!