Individual with a permanent physical disability who has lost all mobility that precludes locomotion without the use of a mechanical aid or prosthesis. You must file the application (Form 458) with the county assessor's office where the original home resides between February 2 to June 30.7. Individuals who have a developmental disability (Form 458B is required). Homestead exemption applications must be filed annually between February 2 and June 30. Application forms are typically available beginning February 2. All forms are fillable. You can fill it out in Reader and print it from there.