the faculty restroom
the staff restroom
the staff's restroom
If anyone thinks of others, I'm sure he/she will add them!
The restroom at school is commonly referred to as the "boys' room" or the "girls' room" for students. These terms are used to indicate the gender-specific facilities. However, schools may also have a separate restroom designated for staff or teachers, known as the "staff room." This is typically a private area for staff members to use during the school day. To provide a more specific answer, it would be helpful to know the context of the question, such as which specific type of restroom you are referring to.