Understanding Legal Domicile in Washington State. Legal domicile in Washington State represents an individual's fixed, permanent home.• Students must live in the state for at least 12 consecutive months as legal residents. All domicile must be established at least one year immediately prior to the first day of the quarter the student is seeking residency. Live in the state for at least 12 consecutive months as legal residents. A Washington domiciliary who intends to move at a future date is still considered domiciled in Washington.