Cal. Water Code § 71250.5

If a director moves his or her residence, as defined in Section 244 of the Government Code, outside the boundaries of that director’s division, and if within 180 days of the move or the effective date of this section, the director fails to reestablish a place of residence within the director’s division, it shall be presumed that a permanent change of residence has occurred and that a vacancy exists on the board of directors pursuant to Section 1770 of the Government Code.