The general deadline for filing an exemption application is before May 1. No information is available for this page.How to Complete the Application. Fill out the other side of this application completely. How To File for Harris County Homestead Exemption - Deadline April 30th. The deadline for filing an application for a homestead exemption in Houston County is April 1. Generally, the filing deadline for a residence homestead exemption is no later than April 30. What if I miss the filing deadline?