“Fences make good neighbors.” There is a dog and cat repellent that can ‘help” dissuade the dogs from using your yard. It is called “Go Away Rabbit, Dog and Cat Repellent” by Bonide. It is a combination of white pepper, cinnamon oil and Thyme oil. You’ll apply the product around the perimeter of your yard so they will smell it and go the other way. Problem is they’ve already claimed your yard as their dumping ground so the product might not work as well as you’d hope. Also, rain washes the repellent away so you’ll need to reapply frequently. A fence would be the only sure fire way to solve this problem. In the meantime, if you see the dog peeing on the lawn, soak the area down right away with a couple of gallons of water. That will dilute the urine enough that it won’t harm the grass.