The court, on motion filed and served concurrently with or before the filing of the answer, shall transfer an action to another county of proper venue if:

1. (1) the county in which the action is pending is not a proper county as provided by this chapter;
2. (2) an impartial trial cannot be had in the county in which the action is pending; or
3. (3) written consent of the parties to transfer to any other county is filed at any time.

Acts 1985, 69th Leg., ch. 959, Sec. 1, eff. Sept. 1, 1985.