Instructions to send a certified letter, return receipt requested. MV-531. Complete and return the form to the Harris Central Appraisal District (HCAD).Q. When does a deferral begin? The Real Property Department records documents pertaining to real property or real estate in Harris County. Attach statement fully explaining project, describe existing site and all proposed improvements, and provide complete detailed (line item). This means that the land is taxed based on the value of what it produces, such as crops and livestock, rather than its sale value. Discover the essential guide to navigating the Harris County Property Tax Website! Write a letter to the assessor. This should include all your intentions. Property tax exemptions.