STATEMENTS. This claim may be used to file for the Homeowners' Exemption for the Assessment Roll and the Supplemental Assessment Roll. Download PDF BOE-266 REV.To qualify for the homeowners' exemption, the home must have been the principal residence of the owner as of January 1 of that tax year. The following is a list of some documents that may be recorded if they meet all requirements, and a description or definition of each document. Automatic Homestead Exemption: This offers limited protection to homeowners without the need to file a formal declaration. Total of 111 forms are available for Contra Costa County for 2024. Exemption forms are due June 30th each year. Once forms are filed exemption is automatically renewed each year. Welcome to the homestead estimated amount page for Single Family Detached homes for Contra Costa county. Many California families are forgetting to claim a common homeowner tax break.