This is the most-used form. But, in formal writing and speaking, you will also hear:
In which house will she live? (Elevated)
This last sentence is what we will call Elevated English. "Elevated" means "put above the rest of us." Some people still think this is the most correct English. It is the language the Queen would use, IF you ever talked to the Queen...:)
Before that time, you can use the one you want. That's one way Globish is different.
End of Lesson G Grammar