How to train my new dog to only go outside?

Since during the past fe weeks this dog successfully adapted to a consistent routine, I wonder if there have been any changes since then (new schedule routine change, changes in the home with regards to humans or pets)?

You may achieve success if you crate train him. It’s usually a process to gradually lengthen time periods in crate- appropriately sized for the dog to be able to turn around and lay down but not too large where it can soil one area. Then when you go out the house, he goes in the crate. When you open crate door, immediately take outside.

There’s another possibility:. Since this dog was a stray in his senior phase of life, a thorough vet exam may rule out that there’s no problems that need to be addressed.

There's a few things you can do, but in this order I would do first.

1.Check it out with the Vet; make sure there are no bowel problems.

1. Deodorize the crap out of your carpet and wherever else he goes in the house. Dogs will "mark" and go potty wherever there is pee and poo smells. So, if your carpet still smells like poo, he will keep doing it. Dogs have 220 million olfactory sensors in their nose, while humans have up to 5 million. That's why dogs can smell way better than us.

2. Keep giving treats and praise every time he does his chores outside. Whether that's in the backyard or on a walk. Make it clear to him, that whenever he goes potty outside, he gets a treat.

3. Its all about timing and correct discipline. Spend the entire day with him, watching everywhere he goes and what he smells. Dogs go to the bathroom based on scent. maybe have him on a leash, so right when he is about to squat and you know he is going number 2, you need to catch it before it happens, and take him outside immediately. Otherwise, if no one tells him no you can't go #2 in the house, he will keep doing it. He has figured out that when you leave the house, that's when he can go, and no one tells him no. Catch them in the act, and redirect him to the correct area to go potty.

Following this helped us the most- Susan Garrett potty train puppy video: https://youtu.be/b1UqsXQBH1A