How do I apply for the homeowner's exemption?

Request the homeowner's exemption through the San Mateo County Assessor's office; the county assessor page lists the exemption amount and application guidance.

How do I appeal my assessed value?

File an application with the San Mateo County Assessment Appeals Board and follow the board's hearing process; the appeals board page explains filing windows and procedures.

San Mateo Property Tax, Exemptions & Appeals Guide

Taxation and Finance California 3 Minutes Read · published March 01, 2026

Property tax administration for residents of San Mateo, California is handled at the county level. This guide explains how assessed value is set, common exemptions, how to appeal an assessment, payment penalties, and the county offices to contact. It summarizes official county procedures and typical timelines to help homeowners, landlords, and non-profit property holders understand next steps and required forms.

This guide summarizes county-administered property tax rules relevant to San Mateo property owners.

Overview

The San Mateo County Assessor-County Clerk-Recorder sets assessed values and manages exemptions. For exemption details and filing instructions consult the county assessor's office.San Mateo County Assessor-County Clerk-Recorder^[1]

Penalties & Enforcement

Delinquent property taxes and late payments are administered by the San Mateo County Treasurer-Tax Collector. Official penalty and interest rules, as well as procedures for tax-defaulted properties and collections, are published by the Treasurer-Tax Collector.

Common monetary penalties: county page lists penalties and interest applied to delinquent secured and unsecured taxes; see the Treasurer-Tax Collector for exact amounts and calculations.^[2]
Escalation: initial penalties and continuing monthly interest may apply; specific escalation rules are provided by the Treasurer-Tax Collector (amounts and schedules on the cited page).
Non-monetary actions: tax-defaulted properties may be subject to sale, liens, or other collection remedies administered by county offices.
Enforcer and contact: Treasurer-Tax Collector enforces payment collection; complaints or payment questions go to the Treasurer-Tax Collector's office.
Appeals and reviews: assessment disputes are handled by the San Mateo County Assessment Appeals Board; filing rules and hearing procedures are set by that board.Assessment Appeals Board^[3]

Missed deadlines for payments or appeals can result in loss of appeal rights or added penalties.

Applications & Forms

Homeowner's Exemption claim: the county assessor describes the homeowner exemption and application process; the assessor page lists the exemption amount and how to apply.^[1]
Disabled Veterans and other specific exemptions: see the assessor's exemption pages for eligibility, required documentation, and submission instructions.^[1]
If a specific form number or fee is not shown on the cited page, it is not specified on the cited page; contact the Assessor or Treasurer for form names and submission steps.

How to Appeal an Assessment

To challenge an assessed value, you must file an assessment appeal application with the county Assessment Appeals Board and follow the board's filing and hearing procedures. The appeals board provides applications, filing instructions, and hearing schedules.

FAQ

Who sets property assessed value for San Mateo properties?: The San Mateo County Assessor-County Clerk-Recorder sets assessed values and manages exemptions and assessment records.
How do I apply for the homeowner's exemption?: Request the homeowner's exemption through the San Mateo County Assessor's office; the county assessor page lists the exemption amount and application guidance.^[1]
How do I appeal my assessed value?: File an application with the San Mateo County Assessment Appeals Board and follow the board's hearing process; the appeals board page explains filing windows and procedures.^[3]

How-To

Gather documentation of market value: recent appraisals, comparable sales, repair estimates, and rent rolls if applicable.
Download and complete the assessment appeal application from the county Assessment Appeals Board or request it from the county office.
File the application within the board's published filing window or within the time allowed after a supplemental or escape assessment, following the board's instructions.
Prepare a hearing binder with evidence and a concise statement of the requested assessed value and attend the scheduled hearing.
If dissatisfied with the board decision, consult guidance on further review rights as published by the county (court remedies may require additional deadlines).

Key Takeaways

File exemptions and appeals with county offices, not the City of San Mateo.
Observe strict filing windows for assessment appeals and payment deadlines to avoid penalties.
Contact county assessor, treasurer, or appeals board for official forms, fees, and submission methods.