Source:
the Humane Society of the United States
You mark your stuff by putting your name on it; your dog marks his with urine. We've covered why dogs mark territory,now here's how to prevent urine-marking behaviors before they happen in your house.
Before doing anything else, take your dog to the veterinarian to rule out any medical causes for the urine-marking behavior. If he gets a clean bill of health, use the following tips to make sure he doesn't start marking his territory.