San Mateo County Assessor – Property Search, APN, Tax Records & Parcel Maps
A San Mateo County property lookup may begin with one address, but the correct result often requires several separate systems. The Assessor and Property Maps portal help identify the APN, assessed value and parcel documents; the Tax Collector handles bills and payments; and the Clerk-Recorder provides the Grantor/Grantee index for deeds and liens. This guide connects those records so homeowners, buyers, condominium owners, coastal-property users, business owners and appeal applicants can complete the right task without treating a map, tax name or third-party report as final legal proof.
Quick Answer: Where to Search San Mateo County Property Records
Use the county Property Maps portal to search parcels by address or Assessor Parcel Number, download Assessor maps and retrieve available recorded maps. Use the Treasurer-Tax Collector’s secured property-tax search to find a bill by address or parcel number. Use the Clerk-Recorder’s Grantor/Grantee index to research property documents recorded since 1985 by party name, document number, document type, recording date, map or book and page.
San Mateo County Property Record Router
Select your task and situation to see the office that should handle the next action.
Your property-record route will appear here
Choose a task and situation to see the correct office, useful records and practical next step.
Important: Planning help only. Not an official tax bill, legal survey, title opinion, assessment decision or government approval.
APN or Address Search Preparation Helper
Use this before opening the county portals when you are unsure which search identifier will work best.
Recommended search plan
Complete the fields to receive a search order, cross-check step and troubleshooting note.
Important: This helper does not access county records or confirm legal ownership.
Supplemental Property Tax Planning Estimator
A change in ownership or completed new construction may create one or two supplemental assessments. Use this to estimate only the possible prorated tax difference.
Supplemental estimate
Enter the new value, prior value, estimated rate and prorated period.
Important: Not an official tax bill, appraisal, escrow quote or government calculation.
Who This San Mateo County Property Guide Helps
Find the APN, check the assessment record, update the mailing address and review homeowners’, veteran or decline-in-value programs.
Research the parcel map, tax bill, supplemental assessment risk, recorded deeds, liens and applicable city or county planning records.
Several units may share a street address. Match the unit, tax bill, deed and parcel number before paying or filing.
Review Assessor and recorded maps for Half Moon Bay, Pacifica, Woodside and unincorporated parcels, but use a surveyor for exact lines.
Review business equipment, supplies, fixtures and leasehold improvements that may require annual business-property reporting.
Use the Assessor or map portal to identify the parcel, then use RecorderWorks for deeds, liens, maps and document indexes.
San Mateo County Assessor Quick Facts
| Item | Current Official Detail | Official Action |
|---|---|---|
| Current Assessor-County Clerk-Recorder | Mark Church | Open the official ACRE website |
| Assessor office | 555 County Center, 3rd Floor, Redwood City, CA 94063-1665 | Appointments and walk-ins are available, subject to service capacity. |
| Main Assessor phone | (650) 363-4500 | Call the Assessor |
| Assessor hours | Monday–Friday, 8:00 AM–5:00 PM, excluding holidays | Verify office access |
| Parcel and map search | Search by property address or APN | Open the Property Maps portal |
| Map downloads | Assessor and available recorded maps may be downloaded online free | Review map instructions |
| Property tax search | Search secured property taxes by address or parcel number | Open Tax Collector services |
| Recorder index | Grantor/Grantee property-document search from 1985 forward | Open RecorderWorks |
| 2026 annual appeal period | July 2 through November 30, 2026 | Open Assessment Appeals |
How to Search San Mateo County Property Records by Address or APN
San Mateo County’s Property Maps portal combines parcel-location tools with downloadable Assessor and recorded maps. The county’s upgraded Property Information Portal also provides property information, assessment data and parcel documents maintained by Public Works and the Assessor.
Use the county portal when you need an APN, map sheet, parcel location or recorded-map reference.
Use APN for the cleanest match. Use address when you do not yet know the parcel number.
After finding the parcel, retrieve the associated Assessor map and save the map name or book-and-page reference.
The portal may provide parcel maps or subdivision maps connected with the selected property.
Before payment, appeal, construction or purchase, make sure the number matches across official records.
How to Research an Owner, Deed or Lien in San Mateo County
The Property Maps portal is not a full online owner-name assessment search. Recorded ownership documents are researched through the Clerk-Recorder’s Grantor/Grantee index. RecorderWorks supports searches by name, document number, document type, map, recording date and book and page.
Use the Property Maps portal or tax lookup to identify the correct parcel before searching names in recorded records.
Search documents recorded from 1985 forward by person or business name. Enter the last name first for individual searches.
Why the Tax Bill May Display Only One Owner Name
Recorder guidance explains that Assessor records may name all parties on a deed while the tax bill displays only the first listed name. Legal ownership should be evaluated from the latest recorded deed and qualified title research—not only the name printed on a tax bill.
Can You View Recorded Document Images Online?
The online index provides reference information but does not include document images for privacy reasons. Use the Clerk-Recorder’s copy-request service or visit the office when an actual recorded document is needed.
Local Search Tips for Redwood City, Daly City, San Mateo, Pacifica and Coastal Parcels
Search strategy changes with the property type. A standard home may be found quickly by address, while a condominium, hillside lot, coastal parcel, mixed-use building or unincorporated property often requires APN and recorded-map cross-checking.
Use the appropriate city planning or building department separately when zoning, permits or local development rules are needed.
County Assessor maps help identify the parcel, but zoning and building questions belong to San Mateo County Planning and Building.
Do not assume that a visible road, driveway or map line establishes legal access or an exact boundary.
San Mateo County Property Tax Search, Payments and Due Dates
The Assessor determines assessed value, but the San Mateo County Treasurer-Tax Collector mails bills, receives payments and handles current-year or delinquent tax questions. The secured property-tax service allows searches by address or parcel number, and no login is required for basic viewing and payment access.
Use the Tax Collector landing page for secured, unsecured and supplemental tax information, service fees and office closures.
Use the county-linked property-tax system to check the tax year, installment, payment status and amount.
| Installment | Due | Payment Deadline | Late Consequence Listed by County |
|---|---|---|---|
| First secured installment | November 1 | December 10 | A 10% penalty is added after the deadline. |
| Second secured installment | February 1 | April 10 | A 10% penalty plus a $40 cost is added after the deadline. |
Supplemental Assessments After Purchase or New Construction
A change in ownership or completed new construction can cause the Assessor to establish a new value. The difference between the previous roll value and the new value becomes a supplemental assessment, which can produce a separate prorated tax bill or refund.
Ask about the old value, new value, reassessment date, ownership event or construction completion used for the supplemental assessment.
Use the Tax Collector for the bill, amount due, payment status and replacement-copy questions.
The Controller computes taxes and can address tax-rate or calculation questions that are separate from assessed value.
Why Some Owners Receive Two Supplemental Bills
Events occurring from January through May may affect both the current fiscal year and the following fiscal year. County guidance explains that this window period can produce two supplemental assessments and therefore two separate bills.
Assessor Maps, Parcel Maps, Subdivision Maps and GIS
The Property Maps portal provides several distinct map products. An Assessor map identifies assessment parcels; a parcel map or subdivision map is a recorded document; and the Property Information Portal can display parcel and assessment data maintained by county departments.
Find the parcel, then retrieve the connected Assessor map and available recorded maps.
Search Assessor maps by book and page or recorded parcel and subdivision maps by volume and page.
Online maps may be downloaded free, while printed or official copies obtained from the Recorder may involve a fee.
Homeowners’ Exemption, Disabled Veterans, Prop 19 and Calamity Relief
| Program | Who It May Help | 2026 or Current Detail | Official Starting Point |
|---|---|---|---|
| Homeowners’ Exemption | An owner occupying the property as a principal residence on January 1 | $7,000 reduction in taxable value; no filing charge; one principal-residence exemption per owner | Review homeowners’ exemption guidance |
| Disabled Veterans’ Exemption | Qualifying disabled veterans and certain unmarried surviving spouses | The official 2026 page lists a basic exemption up to $180,671 and a low-income exemption up to $271,009, subject to eligibility and annual changes | Review 2026 veteran exemption details |
| Proposition 19 | Certain family transfers, owners age 55 or older, severely disabled owners and disaster victims | Eligibility depends on transfer type, residence use, replacement-property value and filing timing | Review Proposition 19 information |
| Calamity Relief | Property damaged or destroyed by fire, earthquake, flood or another qualifying event | Physical damage must exceed $10,000 and the claim generally must be filed within one year | Review calamity-relief requirements |
| Decline in Market Value | Owners whose January 1 market value may be below the factored base-year value | Prop 8 reductions are temporary and reviewed annually until market value reaches the factored base-year value | Review decline-in-value guidance |
Assessor Forms, Mailing Address Changes and Business Property
San Mateo County provides DocuSign forms and downloadable PDF forms for many Assessor services. Use the live forms library instead of an older copy found through a general search result.
Find calamity, mailing-address, ownership, exemption, mapping and property-tax-relief forms.
Submit the secured or unsecured property change-of-address request through DocuSign or the official PDF form.
The statement is generally due April 1 and becomes delinquent after May 7. Confirm the current year’s deadline and filing portal.
San Mateo County Assessment Appeals and 2026 Deadlines
Contact the Assessor first when the property characteristics or assessed value appear incorrect. A conversation or informal review may resolve an issue, but it does not replace the formal Assessment Appeals Board filing deadline.
| Appeal Type | Official Filing Period | What to Prepare | Important Rule |
|---|---|---|---|
| 2026 regular annual assessment | July 2 through November 30, 2026 | APN, tax year, roll value, opinion of value and supporting market evidence | One parcel and one tax year per application |
| Supplemental assessment | Within 60 days of the mailing date on the supplemental notice | Notice, transfer or construction date and valuation evidence | The regular annual filing window does not replace the 60-day deadline |
| Application fee | Due with each application | The current official instructions list a $30 filing fee | Verify online or paper submission instructions before filing |
The roll value being appealed can be found on the tax bill. Record the APN and tax year exactly.
Use comparable sales, appraisal evidence, property-condition records, photographs or documentation of incorrect characteristics.
The county encourages property owners to contact the Assessor soon after receiving an assessment notice.
There are no automatic extensions because an informal discussion is pending.
San Mateo County Property Search Troubleshooting
| Problem | Likely Reason | What to Try Next |
|---|---|---|
| Address search finds several units | Condominium, apartment or multi-parcel building | Match the exact APN to the deed, tax bill and unit number. |
| APN returns no map | Typing error, old parcel number, recent split or incorrect formatting | Compare the APN with the current bill and search the address. |
| Owner name cannot be searched in the map portal | Parcel maps use address or APN rather than Grantor/Grantee names | Use RecorderWorks for recorded documents by party name. |
| Tax bill shows only one name | The bill may display only the first listed name | Review the latest recorded deed for all grantees. |
| Two supplemental bills arrived | The reassessment event occurred from January through May and affected two fiscal years | Compare both bills with the supplemental assessment notice. |
| GIS line differs from a fence or wall | Online parcel lines are reference graphics, not surveyed boundaries | Use recorded maps, title evidence and a licensed surveyor. |
| Recorded document image is unavailable | Images are excluded from the online index for privacy reasons | Order a copy from the Clerk-Recorder or use an in-office terminal. |
San Mateo County Assessor Contact Information and Office Map
Assessor-County Clerk-Recorder: Mark Church
Address: 555 County Center, 3rd Floor, Redwood City, CA 94063-1665
Phone: (650) 363-4500
Email: assessor@smcacre.gov
Hours: Monday–Friday, 8:00 AM–5:00 PM, excluding holidays.
- APN and full property address
- Assessment or tax year involved
- Tax bill, deed, notice or map reference
- Exact error or question you need resolved
- Any filing or payment deadline
Decision Table: Which San Mateo County Office Should You Use?
| If You Need | Correct Office or Tool | Official Next Step |
|---|---|---|
| APN, parcel location, Assessor map or recorded map | Property Maps portal | Search maps by address or APN |
| Assessed value, exemptions, address change or ownership-assessment question | Assessor Division | Open Assessor services |
| Current bill, payment, receipt, supplemental bill or delinquency | Treasurer-Tax Collector | Open Tax Collector services |
| Deed, lien, document number, recording date or recorded ownership history | Clerk-Recorder / RecorderWorks | Search the Grantor/Grantee index |
| Homeowners’, veteran, calamity, Prop 19 or tax-saving form | Assessor forms and tax-saving programs | Open current forms |
| Regular or supplemental assessment appeal | Assessment Appeals Board | Review appeal filing |
| Zoning, permits or allowable development | Applicable city or county planning department | Determine whether the parcel is inside a city or an unincorporated county area. |
After You Search, Pay, File or Request a Record
Common San Mateo County Property Tasks Explained Naturally
How to find an APN when you only know the property address
Search the Property Maps portal by address, open the parcel result and save the APN. Confirm the number against the secured property-tax record before using it for an appeal, payment or deed search.
How to find the owner shown on the latest recorded deed
Search RecorderWorks by Grantor or Grantee name, document number or recording date. The online system covers recorded property documents from 1985 forward, but document images must be obtained separately.
How to check whether property taxes were paid
Use the Tax Collector’s secured property-tax service and search by parcel number or address. Review the tax year and installment before paying again.
How to research a condominium before purchase
Match the unit-specific APN with the deed, tax bill, map and escrow documents. Do not assume every unit in the building has the same assessment, ownership or tax status.
How to review a coastal or hillside parcel
Use the Assessor and recorded maps to identify the parcel, then check access, easements, zoning, building restrictions and environmental requirements with the proper planning office and qualified professionals.
What to do when the assessed value appears too high
Verify the property characteristics, compare the current market value with the factored base-year value, gather January 1 market evidence, contact the Assessor and protect the formal appeal deadline separately.
Official San Mateo County Property Sources
Frequently Asked Questions
How do I search San Mateo County Assessor property records?
Use the official Property Maps portal to search by property address or Assessor Parcel Number. The portal can provide Assessor maps and available recorded parcel or subdivision maps.
Can I search San Mateo County property records by owner name?
The Assessor map search uses address or APN. Use the Clerk-Recorder’s RecorderWorks Grantor/Grantee index to search recorded property documents by person or business name.
What is the San Mateo County Assessor phone number?
The main Assessor Division phone number is (650) 363-4500. Have the APN, property address, tax or assessment year and relevant notice ready before calling.
Where is the San Mateo County Assessor office?
The Assessor Division is at 555 County Center, 3rd Floor, Redwood City, California 94063-1665. Normal business hours are Monday through Friday, 8:00 AM to 5:00 PM, excluding holidays.
How do I look up San Mateo County property taxes?
Use the Treasurer-Tax Collector’s secured property-tax search. You may search by address or parcel number and review or pay the bill online.
Who handles deeds and liens in San Mateo County?
The San Mateo County Clerk-Recorder handles recorded deeds, liens and other real-property documents. RecorderWorks provides an online Grantor/Grantee index for records from 1985 forward.
Are San Mateo County parcel maps free?
The county states that Assessor and available recorded maps can be downloaded online for free. Printed or official copies obtained from the Clerk-Recorder may involve a fee.
Are Assessor maps legal surveys?
No. Assessor and GIS maps are reference tools. Exact property boundaries, easements and encroachments require recorded evidence and, when appropriate, a licensed surveyor.
Why did I receive two supplemental tax bills?
A change in ownership or completed construction occurring from January through May may affect two fiscal years, creating two supplemental assessments and two separate tax bills.
When can I file a 2026 regular assessment appeal?
The official 2026 filing period for regular San Mateo County assessment appeals is July 2 through November 30. Supplemental appeals generally must be filed within 60 days of the notice mailing date.
How much is the homeowners’ exemption?
A qualifying owner-occupied principal residence may receive a $7,000 reduction in taxable assessed value. The claim is filed with the Assessor and there is no filing charge.
Are the calculators on this page official county tools?
No. They are planning helpers only. They do not create an official tax bill, appraisal, legal survey, assessment decision, title opinion or government approval.
What to Do Next
Start with the Property Maps portal when you need an APN, Assessor map or recorded-map reference. Use the Tax Collector for bills and payments, RecorderWorks for deeds and liens, and the Assessor for assessed value, exemptions, mailing-address changes and supplemental-assessment questions. Verify boundaries, zoning, ownership and appeal deadlines through the office or professional responsible for that specific decision.