How to Appeal Your Property Tax in Orange County
Orange County homeowners who believe their property is overassessed can reduce their property tax bill through an appeal. The process has two tracks: an informal review with the Assessor (free, no hearing required, deadline April 30) and a formal appeal to the Assessment Appeals Board (also free, deadline November 30). Most homeowners start with the informal review and file the formal appeal as a backup to preserve their rights.
What are the two ways to appeal my property tax?
Orange County offers two paths: a free informal review through the Assessor's office, or a formal appeal through the Assessment Appeals Board. Both are free to file. Most people start with the informal review — it's faster and doesn't require a hearing.
What is an informal review?
Through the Orange County Assessor Department
The informal review is handled entirely by the Orange County Assessor Department. You download a one-page form, fill in your property details and comparable sales, print it, sign it, and email the scanned form to the Assessor or mail it in. There is no fee, no hearing, and no risk — the Assessor can only reduce your assessed value or leave it unchanged. Results are communicated on your Property Value Notice in July.
- Free to file — no fee
- No hearing required — a certified appraiser reviews your evidence
- File by email or mail — email a scanned signed form to forms.rpsupport@ocassessor.gov, or mail to Orange County Assessor, Attention: Real Property, P.O. Box 22000, Santa Ana, CA 92702-2000
- If the assessor agrees, they adjust your assessed value — and your taxes go down
Submit your informal review request by April 30
The informal review window runs from January 1 through April 30. Email is the fastest way to get your form in — print and sign it, scan it, and send it to the Assessor's dedicated email address. Results appear on your Property Value Notice in July.
What is a formal property tax appeal?
Through the Assessment Appeals Board
The formal appeal goes to the Orange County Assessment Appeals Board, which conducts in-person hearings in Santa Ana. You file a BOE-305-AH application — there is no filing fee. Orange County operates five separate Appeals Boards plus Hearing Officers. The Board can reduce your assessed value, leave it unchanged, or in rare cases increase it.
- Filing window: July 2 – November 30 each year. If November 30 falls on a weekend or holiday, the deadline extends to the next business day at 5:00 PM.
- $0 filing fee — completely free
- In-person hearing before a three-member panel (Santa Ana) — no virtual option
- The board makes an independent determination of your property's value
The online portal does not submit your application
Orange County has an online portal (ODESY) for the formal appeal, but it's a form-completion tool only — it does not actually file your application. You still need to print the completed form, sign it by hand, and mail or deliver it to the Clerk of the Board.
Pro tip: File both tracks. Orange County recommends filing both the informal review and the formal appeal. It's free to withdraw the formal appeal later if the informal review succeeds, and it preserves your rights if it doesn't.
What evidence do I need for a property tax appeal?
Comparable sales are the primary evidence type for Orange County property tax appeals. You need at least three recent sales of similar properties near your home, ideally closed as close to the January 1 lien date as possible. Sales that closed more than 90 days after January 1 (after roughly March 31) are not admissible.
“Similar” means comparable in:
- Square footage and lot size
- Bedrooms and bathrooms
- Condition and age
- Proximity to your home
Bring printed copies to your hearing
If your case goes to a formal hearing, bring six printed copies of all evidence for a Board hearing, or four copies for a Hearing Officer hearing. Do not attach evidence to your appeal application — bring it to the hearing in person.
Free data source: The Orange County Assessor Department provides assessed value data for free at assessedvalue.ocassessor.gov. You can find property details and sales data through the county's parcel information tools.
This is what Overassessed does. We find comparable sales from county records, calculate professional-grade adjustments for differences in size, features, and condition, and package the evidence you need — ready to submit.
The Overassessed Filing Guide includes comparable sales data, dollar adjustments, and a ready-to-submit value argument — everything listed above.
See what's includedHow do I file a property tax appeal step by step?
The Orange County property tax appeal process has two tracks that work together. Here's exactly what to do, step by step.
Check if you qualify
Look up your assessed value at the OC Assessor's property value tool and compare it to what your home would actually sell for. If comparable homes are selling for less than your assessed value, you likely have a case.
Overassessed does this for you — enter your address and we'll pull your assessment and run the comparison.
Gather comparable sales
Find 3 or more comparable sales in your area that closed near the January 1 lien date — sales more than 90 days after that date are not admissible. These are the foundation of your case.
The Overassessed Filing Guide includes selected comps with professional-grade adjustments, ready to submit.
File the informal review
Download the Request for Informal Assessment Review (A002-259A), fill it in with your property info and comps, print and sign it, then email the scan to forms.rpsupport@ocassessor.gov or mail it to Orange County Assessor, Attention: Real Property, P.O. Box 22000, Santa Ana, CA 92702-2000. The deadline is April 30.
File the formal appeal as a backup
File the BOE-305-AH formal appeal application during the July 2 – November 30 window. It's free, and you can withdraw it later if the informal review succeeds.
Prepare for your hearing
If your formal appeal goes to a hearing, prepare your evidence package and bring printed copies to the in-person hearing in Santa Ana. Bring 6 copies for a Board hearing or 4 for a Hearing Officer hearing.
Our Filing Guide gives you copy-paste values for every field on the county form, plus a deadline tracker.
Check if you qualifyImportant things to know
The online portal is not a filing portal
Orange County has an online portal for the formal appeal, but it doesn't actually submit your application. You still need to print the completed form, sign it by hand, and mail or deliver it. Don't assume you're done after completing it online.
You can email your informal review form
The fastest way to file your informal review is by email. Print and sign the form, scan it, and email it to the Assessor's dedicated address (forms.rpsupport@ocassessor.gov). This is faster than mailing, but you still need a handwritten signature — electronic signatures are not accepted.
Hearings are in-person only
If your formal appeal goes to a hearing, you'll need to appear in person at the county offices in Santa Ana. There is no virtual hearing option in Orange County. If you can't attend, you can authorize an agent to appear on your behalf.
No filing fee for either track
Orange County does not charge a fee to file an assessment appeal or an informal review request. Both tracks are completely free.
Frequently asked questions about Orange County property tax appeals
What is the deadline to appeal property taxes in Orange County?
Orange County has two deadlines. The informal review (Decline-in-Value request) must be submitted to the Assessor by April 30. The formal Assessment Appeal Application must be filed with the Clerk of the Board between July 2 – November 30. If November 30 falls on a weekend or holiday, the deadline extends to the next business day at 5:00 PM. Filing both is recommended.
How much does it cost to appeal my property tax in Orange County?
Both tracks are free. There is no fee to file an informal review with the Assessor and no fee to file a formal assessment appeal with the Clerk of the Board. Orange County does not charge a filing fee for either track.
Do I need a lawyer to appeal my property taxes in Orange County?
No. Most residential property owners in Orange County represent themselves at assessment appeal hearings. You do not need a lawyer, tax consultant, or agent. If you prefer to have someone represent you, you can authorize an agent using the county's Agent Authorization form — but it's not required.
What evidence do I need for a property tax appeal in Orange County?
The best evidence for a residential appeal is three or more comparable sales of similar properties in your area. Sales should be as close to the January 1 lien date as possible — the Board cannot consider sales more than 90 days after that date. Bring six printed copies of all evidence to a Board hearing, or four copies if you chose a Hearing Officer hearing.
How long does a property tax appeal take in Orange County?
The informal review results appear on your Property Value Notice in July — no separate hearing is needed. If you file a formal appeal, hearings are typically scheduled six to nine months after filing. You'll receive a hearing notice at least 60 days before your scheduled date. The county has up to two years to schedule your hearing, though most cases are heard sooner.
Can the Assessment Appeals Board increase my property taxes in Orange County?
The formal Assessment Appeals Board does have the legal authority to increase your assessed value, though this is rare in practice. This is one reason the informal review is recommended as the first step — the Assessor can only reduce or confirm your value, never increase it. If you have strong comparable sales supporting a lower value, the risk of an increase at a formal hearing is minimal.
Ready to see if you qualify?
Enter your address and we'll compare your assessed value to comparable sales. It takes about 60 seconds.
Overassessed provides estimates based on publicly available data and AI-generated analysis. This is not a formal appraisal, legal advice, or tax advice. Results are not guaranteed, and appeal outcomes depend on county review. Users file their own appeals. AI-generated estimates may differ from actual market values.