D.D.
How often do you take him out and get him really tired? A tired dog is a good dog. He needs to get a lot of exercise so walking him in the neighborhood might be a good idea. He'll pee on everything to mark his territory (which is basically anything he feels like peeing on) and come home feeling more relaxed.
As far as leaving him alone? You can't. When I first got my rescue dog he was 2 yrs old and had never lived in a house. Not house broken at all. I had him leashed so he was always right there with me. After a while I unleashed him in the house but called him to follow me to where ever I was going so he wasn't alone. That along with a couple walks a day cut out the in the house marking.
The reason he's not marking in the laundry room is because that's his den; where he sleeps and feel safe. He doesn't have to mark it because he feels he owns it already.
He needs to see that you are the top dog so put your training skills to use every single day so that he's not the dominate one in the house. Make him sit while you give your other dog food or something of high dog value. Once she's established then give him something. Be bossy to show him that he doesn't choose what the other dog can and can not have. Throw him on a leash if he's not behaving. Be a top dog.