My 14 month old female, named Mitzi

, has stopped peeing on peepads and is going on area rugs. I don't understand why in the last couple of months she has been doing this and I am not sure how to change it. When she goes for her walks she always goes on grass and maybe she doesn't like the peepads anymore.
Has anyone had similiar problems that could help me?
Thanks kindly,
Nikki