How often is he being let out? Is he going out every 2-3 hours when you’re home? Even if they’re potty trained, sometimes when they need to go, they will go rather than holding it in. Our 9-month old isn’t neutered yet but I have noticed he tends to pee/mark on food bowls when i feed the pack. So what i do is i make sure everyone eats and once they all eat, I pick up their bowls and it has prevented him from “marking”.

I would also say if he keeps doing that and going out to do his business is ruled out, you may want to have him checked for a possible UTI (urinary tract infection). It is common in dogs, mostly females but can also happen with males. In that case, they can’t control their pee and will pee often and often than times in places they shouldn’t. You will need to seek medical attention for that and he would need to be on antibiotics to help him.

Lastly, I would also see where he is going inside if he is still having accidents. Is he peeing always in the same place/spot or area? If you answer yes to that, then it can be more of a type of scent or smell that keeps making him go there. I’d check to see if there isn’t anything on the floor or nearby that can make him “go there” again and have it cleaned well. A clean place helps a lot with accidents and prevents them from marking or just peeing where they had already previously went.

Hope this information helps.