Fortunately we have a condo rented out and dogs are not allowed according to the bylaws. My mother's experience about 15 years ago was really bad. She unknowingly rented out her row house in the UK to a drug addict who had a dog. After minimal rent and damage deposit received the tenant did not pay any more rent for the whole year.
Now folks take advantage of an older woman landlord namely my mother and after a year she got the bailiff to boot out the tenant. Now just coz your tenant has been good so far does not mean that the dog will be just as good. If it was me I would say no to the dog. Are you really prepared for what can happen? Dog smell, dog damage etc.
If it was me I would say no to the dog. If she wants a dog still tell her to move. Sorry but I can be a cruel heartless asshat when it comes to my property. Tenants are tenants for a reason. Good luck! It may turn out okay but it may not.
Cheers, Guy
