STATEMENTS. This claim may be used to file for the Homeowners' Exemption for the Assessment Roll and the Supplemental Assessment Roll. Welcome to the homestead estimated amount page for Single Family Detached homes for Contra Costa county.Download PDF BOE-266 REV. How to File a Homestead Exemption. A homeowner must file for the homestead exemption with the correct county recorder's office. The County Clerk-Recorder's Office maintains real property records back to 1849. You may search our online index back to 1986. Once forms are filed exemption is automatically renewed each year. Total of 111 forms are available for Contra Costa County for 2024. The application filing period is from January 1st through December 31st.