How old is she? That makes a huge difference. Some dogs know they need to go outside but can't hold it or can't learn to tell you. Loki peed on the doormat for months until we taught him to ring bells so that we could hear him when he wanted to go outside. The accidents stopped almost immediately.
When we got Sammy she was almost a year old but was not housetrained. She would just stop and pee wherever she wanted. It took her MONTHS to understand the concept of the bells. We ended up having to take her out OFTEN, and constantly watch her and even tether her to us with her leash. We reward her with an awesome great every time and tell her how good she is. Sammy likes to please us. Loki was all about the food and could care less if we were happy as long as he got a treat
