The deadline to file for the full exemption is February 15. Tax Exemption forms, Assessor Department (714) 834-3821 ; W-9.To claim the exemption, the homeowner must make a one-time filing with the county assessor where the property is located. Download PDF BOE-266 REV. We are unable to accept online filings. Complete form BOE-266, Claim for Homeowners'. Property Tax Exemption. Application for exemption must be filed before April 1 of the assessment year with the county assessor. The application must be refiled every even year. Please Download PDF BOE-260-B REV.