County filing guide
How to appeal your property tax in Stanislaus County
Regular decline-in-value appeals. Supplemental and escape assessments have different deadlines.
Filing options
A filing-fee waiver may be available. Check with the county to see whether you qualify.
Filing instructions
Informal review with the Assessor
Request a review by December 31, 2026 for the 2026-27 assessment. An informal request does not preserve your right to a formal appeal; the formal deadline comes earlier.
Open the Assessor's Decline in Value (Prop 8) page. Have your assessment notice or tax bill, parcel number and property address ready.
Call the Assessor at 209-525-6461, Monday–Friday, 8:00 a.m.–4:30 p.m., and ask for an informal decline-in-value review. You can also contact staff at [email protected].
Call the Assessor to request an informal review. Explain why you believe the January 1, 2026 market value is below the taxable value. Have your proposed value and comparable-sales information ready, and ask staff how they want you to provide supporting material. The Assessor performs a comparable-sales analysis to decide whether the property qualifies.
Keep a copy of anything you send and a record of the request. If the matter is unresolved as the formal deadline approaches, file a separate formal appeal by that deadline. Continue paying property taxes when due.
Formal appeal by mail
The Clerk's published regular-assessment filing window is July 2, 2026–November 30, 2026. The processing fee is $30 per application.
Open the county's Assessment Appeals page. Under Assessment Appeal Forms, download Assessment Appeal Application and Instructions for Assessment Appeal Application.
Download the application and read its instructions. Complete one application per parcel and roll year. Enter your name, mailing address and contact details, then copy the parcel/assessment identifiers and property address from your notice or tax bill. Complete the representative information only if someone is acting for you.
Fill in the assessed values and your opinion of value for the applicable categories. Leave the appeals-board column blank. For an ordinary annual market-value dispute, select Regular Assessment for the correct roll year and Decline in Value.
Read the application's instructions before answering the written-findings and claim-for-refund questions. Review the certification, identify your filing status, then print, sign and date the application. Original signatures are required.
Include two copies of the assessment notice or tax bill and a $30 check or money order payable to County of Stanislaus. Keep hearing evidence separate from the initial application. Make a copy of the complete packet for your records.
Mail the signed application, required copies and fee to Stanislaus County Assessment Appeals Board, 1010 10th Street, Suite 6700, Modesto, CA 95354. Obtain a USPS postmark on or before November 30, 2026, and retain proof of mailing. Applications without the fee are returned unprocessed.
Retain your application number and county correspondence. The Assessor may contact you to discuss a value agreement; otherwise follow the hearing notice and prepare your evidence. Filing an appeal does not postpone tax payments.
After you file
Informal review
Keep your request confirmation and any correspondence from the Assessor. Check the formal appeal deadline above when considering a separate appeal.
Formal appeal
Keep a copy of your application and filing confirmation. Watch for notices from the Clerk of the Board and follow the county’s instructions for any hearing.
Open my appeal plans →Contacts & sources
Clerk of the Board
Runs the formal appeal
209-525-6414 · appeals page ↗
1010 10th Street, Suite 6700, Modesto, CA 95354
This guide covers the regular decline-in-value appeal; supplemental or escape assessment notices follow different deadlines. Every date and fee here was checked against official sources, listed below with the date checked. If the county's page ever differs from this guide, follow the county's page.
Sources
Informal sources
- Assessor: Decline in Value (Prop 8) — rechecked in the browser October 6, 2026; annotated contact screenshot added beneath informal Step 2. Supports contact-based review, the December 31 cutoff, January 1 valuation and the Assessor's comparable-sales analysis. Requests after December 31 concern the following fiscal year.
- Assessor's Office and Assessment Appeals — contact details and invitation to discuss the assessment with staff. No dedicated informal online submission form or downloadable review application was found in the reviewed official material. The Assessor's “e-File” link concerns property statements and is not presented here as an informal-review portal. The suggested information to have ready is preparation guidance, not a claimed mandatory county checklist.
Informal review
- https://www.stancounty.com/assessor/DeclineInValue.shtm · “Requests for a review for the current fiscal year would need to be made by December 31 of that fiscal year. Requests received after this date would be reviewed for the following fiscal year.” (checked July 11, 2026)
Formal sources
- Assessment Appeals and Appeals FAQ — reviewed September 29, 2026. Confirm the July 2–November 30, 2026 regular window, USPS-postmark rule, one application per parcel, $30 nonrefundable fee and mailing address. The FAQ confirms the payment recipient and that applications without payment are returned.
- Application and included instructions and county filing instructions — support the form content, original signature, two notice/tax-bill copies and paper submission. No electronic submission channel was identified in the reviewed county materials. This walkthrough covers a regular annual decline-in-value appeal; supplemental, escape and other notice-based appeals have separate deadlines.
- Current linked application instructions — inspected October 6, 2026. The county's styled Assessment Appeals page and form links were checked in the browser; an annotated download screenshot is beneath formal Step 1. Later paper-form steps remain document-backed; no application was submitted.
- Deadline discrepancy: the Assessor homepage says December 1, 2026, while the Clerk's current filing page, FAQ and filing instructions say November 30. This guide follows the Clerk's November 30 deadline. The Clerk can clarify at (209) 525-6414; do not rely on the later date without confirmation.
Formal appeal window
- https://www.boe.ca.gov/proptaxes/pdf/lta26023.pdf · “The regular appeals filing period in each county will begin on July 2, 2026, and will end on September 15, 2026, for those counties where the Assessor mails assessment notices to all taxpayers with property on the secured roll by August 1, 2026. For counties where assessment notices are not mailed by August 1, 2026, the filing period is extended to November 30, 2026.” (checked July 10, 2026)
Filing fee
- https://www.stancounty.com/board/aab/aab-faq.shtm · “Yes, there is a $30.00 processing fee for each application filed. Receipts will be issued for cash payment only.” (checked July 11, 2026)
Filing address
- https://www.stancounty.com/board/aab/aab-faq.shtm · “Applications for Changed Assessment forms are available at the Assessment Appeals office at 1010 10th Street, Suite 6700, online or if you wish to receive an application by mail, you may call our office at (209) 525-6414 and request an application.” (checked July 11, 2026)
- https://www.stancounty.com/board/aab/ · “1010 10th Street, Ste 6700 Modesto, CA 95354” (checked July 11, 2026)
Filing channels
- https://www.stancounty.com/board/aab/pdf/AABInstructionsRevFilingFee.pdf · “Please Mail Completed Application and $30.00 Processing Fee to: Stanislaus County Assessment Appeals Board 1010 Tenth Street, Suite 6700, Modesto, CA 95354” (checked October 7, 2026)
Fee waiver
- https://www.stancounty.com/board/aab/aab-faq.shtm · “Fees are non-refundable, but may be waived where the application would qualify for a waiver of court fees and costs pursuant to Government Code Section 68511.3.” (checked July 11, 2026)
Common questions about appealing in Stanislaus County
When is the deadline to appeal in Stanislaus County?
The deadline to file a formal appeal in Stanislaus County for the 2026-27 tax year is November 30, 2026. Filing opened July 2, 2026.
The Assessor takes informal review requests until December 31, 2026.
What does it cost to file an appeal in Stanislaus County?
The county filing fee for a formal appeal is $30.
A filing-fee waiver may be available. Check with the county to see whether you qualify.
Informal review or formal appeal: which one first?
Stanislaus County offers both: an informal review with the Assessor, and a formal appeal filed with the Clerk of the Board (due November 30, 2026).
The state's own guidance says to talk to the Assessor's office first: if their staff finds an error, they can lower the roll directly and you may never need to file. Missing an informal review costs you nothing; missing the formal deadline costs you the year.
Which form do I file, and where?
We have not established which application form Stanislaus County requires.
Stanislaus County accepts the formal appeal by mail.
Mail it to the Clerk of the Board at 1010 10th Street, Suite 6700, Modesto, CA 95354.
Check the Clerk of the Board's appeals page ↗ or call 209-525-6414 before you file.
How long does an appeal take?
You get written notice at least 45 days ahead, hearings are open to the public (you can watch one first), and boards are expected to decide within two years of filing. You can still settle at any point before your date.
Do homeowners actually get their assessments lowered?
3,713 homes in Stanislaus County had temporarily reduced assessments in tax year 2025-26.