If your dog is peeing in the house it's probably because a) he doesn't know that he's not supposed to do that, or b) he knows better but the need to for peeing in the house outweighs the need for your approval or the fear of your disapproval. Let's look at some reasons for dogs peeing in the house.
Marking is the process of a male dog staking out his "turf". Dog urine tells other dogs a whole lot about the marker; size, weight, demeanor, age and what a dog had for his last meal can all be sensed by another dog.
But mostly dog urine says "This is my territory and you'd better stay outta here!" Male dogs hit dog adolescence around 9 months and, just like adolescent boys, start getting all macho. If you find that your young dog is peeing in the house it's a great time to discuss the benefits of neutering your dog with your vet.
Look for physical symptoms. Is she eating? Is she drinking more water than usual? How's your dog's mood, her activity level? How old is she? The answers to these types of questions may unearth a medical reason for your dog peeing in the house.
If you find yourself answering "yes" to any of these questions you may need to grab your checkbook and head for the vet. I'd recommend taking a urine sample with you, by the way, unless your dog has been trained to pee in command.
If you've eliminated the physical reasons for your dog peeing in the house you may look into psychological reasons. My experience with my own dogs leaves me with no doubts as to their ability to experience emotions we usually do not associate with our k9 friends. Anxiety, nervousness, jealousy and depression could all be reasons your dog is peeing in the house. There are professionals who are qualified to deal with these afflictions (I am not one of them!). An Internet search for "dog psychologist" or a recommendation from your vet should steer you toward a solution.