I would start with housetraining much sooner and put in a doggy door BEFORE I got him, to make potty training more successfull. I would make sure that he knew that pottying inside is never okay.
The last time we visited my parents he soiled their carpets and they had to have it professionally washed.
I didn't know anything about pottytraining and now, at 5 months, he still isn't potty-trained. Going to try using a clicker for this as well. Keeping my fingers crossed.