My dog pees inside when I'm gone. How do I stop house marking?

Hello, sorry to hear about Buddy. It sounds like he is indeed marking his territory when you're not home. I think the crate is a great idea, but if you need some time to get him used to this, a small room such as a bathroom or bedroom would also limit the areas where he marks in the house. Additionally, taking him out to go to the bathroom before you leave will also decrease the amount of urine he has to mark with.

A dog urinating on objects, usually vertical, is a normal, instinctive social behavior. Dogs mark their territory by urinating on certain objects within their territory. The dog returns to these spots on occasion to renew this olfactory mark. Usually the amount of urine produced is a smaller amount than when the dog relieves himself. Marking often occurs in areas where other dogs have urine marked or left there odor. Although more commonly seen in intact males, neutered males and females also mark.
What is inappropriate marking? Inappropriate marking is when an otherwise healthy, housetrained dog marks objects in an area that is not acceptable to the owner, such as inside a home.
Why is my dog inappropriately marking?
Causes of inappropriate urine marking can be hormonal or social. Social factors include situations that cause anxiety or territorial stimuli, such as other animals entering their “territory,” or the introduction of something new, such as grocery bags, people, or furniture. Dogs with other anxieties, such as separation anxiety or noise phobia, can also mark.
What can I do to prevent inappropriate marking?
• If your dog is intact, neuter your dog. One study found that 40% of male dogs castrated for marking drastically decreased their marking, regardless of age of castration.
• Neuter all animals in household. Hormonal changes in other animals, like female dogs in heat, may trigger marking.
• It is important to rule out underlying medical problems that may cause inappropriate urine marking. The stress of medical problems can be a contributing factor to marking.
• Clean up residual odors of the urine with enzymatic cleaners.
• Block or eliminate provoking stimuli, such as cover windows where your dog can see other dogs walking by, block access to room where dog may hear other dogs walking by.
• Have a conversation with your veterinarian about separation anxiety or other anxieties to determine if this is the cause of inappropriate urine marking. Treat these underlying causes.
• Do not place new objects on floor until your dog has gotten used to having them in the house.
• During training, when your dog cannot be supervised, he should be confined to a smaller area so that he does not practice inappropriate urine marking when the owner is not home. He may subsequently learn that it is acceptable to mark when the owner is away.
• Establish conspicuous objects outside the house where marking is acceptable, and reward for acceptable marking.
• Change the emotional state of your dog around target areas to pleasurable areas of play or eating
• In dogs with extreme anxiety, anti-anxiety medications may be beneficial.
• Establish leadership from the owner and routine in the dog’s life by implementing non-confrontational leadership exercises.