Pet Sitter Needed

My dog is 8 months old and needs potty training. Potty trained as a puppy when we first got him, but still pees and poops in the house, even when the door to the backyard is open, he will rarely go out by himself. He can hold his bladder on road trips and overnight, but will go to the bathroom in the house whenever he feels like it. We either take him outside in the backyard or take him for a walk every 2 hours. He just needs to know he cannot go to the bathroom in the house.