Property Tax Appeals in Marin County, California
Marin County's Board of Supervisors page states that a completed Assessment Appeal application, filled out in blue ink, must be mailed or dropped off with a $50 non-refundable processing fee, payable by check or money order to "County of Marin." The page does not describe an online e-filing system; applications are directed to the Assessment Appeals Clerk at 3501 Civic Center Drive, San Rafael, CA 94903. Marin also requires the applicant to attend the scheduled Assessment Appeals Board hearing in person, or the Board will not consider the appeal request. FairPath can organize an owner-managed comparison table, condition exhibits, official links, and a filing checklist. It does not file the application, select the owner's opinion of value, pay the fee, negotiate with the Assessor, or appear at the hearing.
Assessment context: Begin with the Assessor's parcel record and confirm whether the dispute concerns the January 1, 2026 lien-date value on the regular roll, a supplemental assessment, a roll change, an escape assessment, or a calamity reassessment. Marin County combines the urbanized US-101 corridor from San Rafael to Novato, affluent Bay-side and coastal communities such as Tiburon, Sausalito, and Stinson Beach, and rural West Marin agricultural and coastal-protected land. A West Marin agricultural parcel is not automatically comparable to a San Rafael subdivision lot. Zoning, coastal-access restrictions, agricultural preserve status, and site condition should be confirmed against the Assessor's record rather than assumed from a map.
Filing process: Meet with the County Assessor to discuss the assessment before filing, since an agreement with the Assessor can resolve the disagreement without a Board appeal. Download the Assessment Appeal application, or pick up a copy at the Assessment Appeals Board office, and fill it out in blue ink; a separate application is required for each parcel and assessment type. Mail or drop off the completed application with the $50 non-refundable processing fee, paid by check or money order to "County of Marin," to the Assessment Appeals Clerk, 3501 Civic Center Drive, San Rafael, CA 94903. After submission, the county mails a confirmation letter, and a complete application later receives a Notice of Hearing and Hearing Date Confirmation form 45 days before the hearing, which must be returned at least 21 days before the hearing date. Property taxes remain due while the appeal is pending.
Evidence to review: Marin County's Board of Supervisors page offers a Residential Property Tax Comparison Work Sheet as supplemental information for building an appeal, and requires the applicant to attend the scheduled hearing in person and present the case to the Assessment Appeals Board, or the Board will deny the application. Build a comparable-sales table showing sale date, price, parcel, community, lot size, living area, age, and condition, and prioritize sales close to the January 1, 2026 lien date; California generally excludes comparable sales occurring more than 90 days after that date. For West Marin agricultural or coastal-protected parcels, document zoning, access limitations, and any physical limitations with dated photographs or inspection findings.
Current deadline guidance: 2026 regular assessment appeals: July 2 through November 30, 2026. Marin County's Board of Supervisors page lists Application deadlines for Regular assessments as July 2 - November 30, by 5:00 p.m., consistent with the California State Board of Equalization's certified county filing-period table. Supplemental assessments, roll changes, and escape assessments must instead be filed no later than 60 days after the postmark date on the tax bill, and calamity reassessments within six months of the postmark date on the reassessment notice.
Marin County's 2026 Regular Assessment filing period runs July 2 through November 30, by 5:00 p.m., matching the state's extended deadline group.
The Assessment Appeals Clerk charges a $50 non-refundable processing fee per application, payable by check or money order to "County of Marin."
Marin County's posted instructions describe a mailed or dropped-off paper application in blue ink; an online e-filing system is not described.
An applicant must attend the scheduled Assessment Appeals Board hearing in person, or the Board will not consider the appeal request.
Official filing authority: Marin County Assessment Appeals Clerk, Board of Supervisors. https://www.marincounty.gov/departments/board/appeal-your-property-tax-assessment
Source: Marin County Board of Supervisors, Appeal your property tax assessment, https://www.marincounty.gov/departments/board/appeal-your-property-tax-assessment. Reviewed 2026-09-22.
Source: Marin County Board of Supervisors, Property tax assessment appeals, https://www.marincounty.gov/departments/board/property-tax-assessment-appeals. Reviewed 2026-09-22.
Source: California State Board of Equalization, Letter to Assessors 2026/023: 2026 Assessment Appeal Filing Periods, https://boe.ca.gov/proptaxes/pdf/lta26023.pdf. Reviewed 2026-09-22.
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