In an English-speaking country, how would a household employee address their female employer? [closed]

People still employ cleaning ladies, dog-walkers, lawn-mowers, and snow shovelers; these are not full time servants who work only for this person, but they are household employees. In my experience in Canada the existence of an employer-employee relationship doesn't change what people call each other: an adult would call me Kate by default and a child might call me Mrs Gregory or Kate depending on their age and our existing relationship (eg neighbor children might have already been invited to call me Kate.)

If your question applies specifically to full time employees who work for only one family and share a home with them, then I would not be surprised to hear a more formal address (eg Mrs Gregory, or if I had a title perhaps Your Grace) simply to keep the distinction between friend/family/roomate and employee clear. Also certain occupations have a tendency to give their employees titles (eg nannies might call all the moms Mother, all the dads Father) -- these are occupations in which the employee is, to a certain extent, setting the rules of engagement. A pool boy would not do this. A tennis coach might.