STATEMENTS. This claim may be used to file for the Homeowners' Exemption for the Assessment Roll and the Supplemental Assessment Roll. A new owner will automatically receive an exemption claim form in the mail and there is no cost to file.Welcome to the homestead estimated amount page for Single Family Detached homes for Contra Costa county. Download PDF BOE-266 REV. Exemption forms are due June 30th each year. Once forms are filed exemption is automatically renewed each year. Complete and submit the application: Obtain the right form from the county assessor's office (or their website) and fill it out accurately. Total of 111 forms are available for Contra Costa County for 2024. The Housing Authority of the County of Contra Costa accepts pre-applications online when we anticipate housing becoming available within a few months. What is the Homestead Exemption benefit?