You have several options when you receive a Notice of Supplemental Assessment — and each one comes with its own deadline, benefit, and risk. Under California Revenue and Taxation Code §75 et seq., the county assessor must reappraise your property whenever a change in ownership or new construction occurs, and that reassessment creates a supplemental tax bill on top of your regular annual property tax bill. Roughly 1 in 5 California homeowners who receive a supplemental assessment notice overpay because they fail to review the assessed value, miss the 60-day appeal window, or don’t apply for available exemptions.
Here is what you will learn in this article:
- 🏠 What a Notice of Supplemental Assessment is and why you received one
- ⚖️ The five specific options you have — including how to file an appeal before the deadline runs out
- 💰 How to calculate whether you are owed a refund instead of a tax bill
- 🚫 The most common mistakes homeowners, investors, and new buyers make — and the exact financial consequences of each
- 📋 A full walkthrough of Form BOE-305-AH, the hearing process, and what evidence you need to win
Property Tax Is a State and Local Matter — Not Federal
The U.S. federal government does not assess, collect, or regulate property taxes. Property taxation is entirely a state and local function. The IRS allows property tax deductions under 26 U.S.C. § 164, but it plays zero role in how your property is assessed. Every state has its own system for valuing real property and collecting taxes on it.
California’s supplemental assessment system is unique among the 50 states. It exists because of Proposition 13, the landmark 1978 ballot measure that capped annual property tax increases at 2% per year. Most other states reassess property on a regular cycle — annually, biennially, or every few years — and do not need a separate “supplemental” roll. California does, because its base year value system only allows reassessment when specific triggering events happen.
States like Florida, Texas, and New York reassess property values every year or on a fixed schedule. They don’t issue supplemental assessments. If you own property outside California, you typically receive one annual tax bill that reflects the current year’s full assessed value. The supplemental assessment concept applies almost exclusively to California property owners.
What a Notice of Supplemental Assessment Actually Means
A Notice of Supplemental Assessment is a formal document mailed to you by the county assessor after your property undergoes a change in ownership or completion of new construction. It tells you the difference between the property’s old assessed value and its new assessed value. This difference — called the net supplemental assessment — becomes the basis for an additional tax bill or refund.
The California State Board of Equalization explains it with a simple formula. The assessor takes the new base year value (the current market value at the time of the event), subtracts the prior assessed value, and the result is the net supplemental assessment. If that number is positive, you owe more tax. If it is negative, you are entitled to a refund.
| What the Notice Shows | What It Means |
|---|---|
| New base year value of $400,000 | The assessor’s opinion of your property’s current market value |
| Minus prior assessed value of $300,000 | The previous owner’s assessed value (or your pre-construction value) |
| Equals net supplemental assessment of $100,000 | The taxable difference — you owe additional property tax on this amount |
This notice is not a tax bill. It is the assessment notice. The actual supplemental tax bill comes later, usually three to six months after the triggering event. You need to review the notice carefully because your 60-day appeal clock starts when the notice is mailed — not when you receive the tax bill.
Why Proposition 13 Triggers This Whole Process
Proposition 13, codified in Article XIII A of the California Constitution, fundamentally changed how property is taxed in the state. It set three core rules that still apply today: the property tax rate is capped at 1% of assessed value (plus voter-approved bonds), the assessed value can only increase by a maximum of 2% per year, and the property is only reassessed to current market value upon a change in ownership or new construction.
The practical effect is that a home bought in 1990 for $200,000 could have an assessed value of about $395,000 today — even if its market value is $1.2 million. The property stays at the lower Prop 13 value until a reassessment trigger occurs. When you buy that home for $1.2 million, the county assessor establishes a new base year value at the purchase price.
The supplemental roll exists to bridge the gap between the old assessed value and the new one. Without it, the county would have to wait until the next annual assessment roll to reflect the new value — meaning the new owner would pay taxes based on the old owner’s artificially low Prop 13 value for months. Revenue and Taxation Code §75 et seq. created the supplemental assessment process specifically to fix this gap.
The Two Events That Create a Supplemental Assessment
Only two types of events trigger a supplemental assessment in California: a change in ownership and completion of new construction. The county assessor calls these “supplemental events.” Everything else — market fluctuations, inflation, neighborhood changes — does not trigger a supplemental assessment.
A change in ownership includes the sale of a home, a transfer to a non-exempt party, certain changes in legal entity ownership, or the transfer of controlling interest in a corporation or LLC that holds real property. Parent-to-child transfers may qualify for an exclusion from reassessment under Proposition 19 (which replaced the old Proposition 58 rules), but a claim form must be filed.
Completion of new construction means any addition, alteration, or improvement that creates new square footage, adds a fixture, or constitutes a substantial equivalent of new construction. Adding a bedroom, building a pool, or converting a garage into a living space all qualify. Routine maintenance and cosmetic repairs do not trigger reassessment.
| Subject to Supplemental Assessment | NOT Subject to Supplemental Assessment |
|---|---|
| Land, improvements, and fixtures upon change in ownership | Personal property (boats, aircraft, business equipment) |
| New construction that adds value or square footage | Williamson Act (agricultural preserve) property |
| Taxable possessory interests upon transfer | Restricted historical property |
| Transfers of controlling interest in LLCs/corporations holding real property | State-assessed property (railroads, utilities) |
How the County Auditor Calculates Your Supplemental Tax
The county assessor determines the new value and sends you the notice. The county auditor-controller then calculates the actual tax using the net supplemental assessment, the local tax rate, and a proration factor based on when the event occurred. The tax covers only the months remaining in the current fiscal year (July 1 through June 30).
The number of supplemental tax bills you receive depends on when the event happens. If the supplemental event occurs between June and December, you get one bill covering the remainder of the current fiscal year. If the event occurs between January and May, you get two bills — one for the remaining months of the current fiscal year, and a second for the entire following fiscal year.
| Month of Event | Bills You Receive | What They Cover |
|—|—|
| June through December | 1 bill | Remaining months of the current fiscal year |
| January through May | 2 bills | Bill #1: remaining months of the current fiscal year; Bill #2: the full next fiscal year |
The proration factor is straightforward. If the event happens in October, the tax becomes effective November 1, and there are 8 months left in the fiscal year (November through June). The proration factor is .67 — meaning you pay 67% of what the full annual supplemental tax would be. A July event uses a factor of 1.00 (full year), while a May event uses .17 (only 2 months left).
Scenario 1: Maria Buys Her First Home in October
Maria purchases a home in October 2025 for $550,000. The previous owner’s assessed value was $380,000. Maria’s net supplemental assessment is $170,000. Her local tax rate (including voter-approved bonds) is 1.1%. Because the event occurs in October, the tax is effective November 1, and there are 8 months remaining in the fiscal year.
| Step | Result |
|---|---|
| New base year value (purchase price) | $550,000 |
| Minus prior assessed value | $380,000 |
| Net supplemental assessment | $170,000 |
| Annual supplemental tax ($170,000 × 1.1%) | $1,870 |
| Proration factor (November 1 = .67) | .67 |
| Maria’s supplemental tax bill | $1,252.90 |
Maria receives one supplemental tax bill because her purchase occurred between June and December. This bill is in addition to the regular annual tax bill she will also receive. If Maria qualifies for the $7,000 homeowner’s exemption and files a claim, the exemption is deducted from the supplemental assessment before the tax is calculated. The exemption would reduce her net supplemental assessment from $170,000 to $163,000, lowering her bill.
Scenario 2: David Completes a Major Addition in February
David finishes building a new master suite and bathroom onto his home in February 2025. The county assessor values the new construction at $95,000. Because the event occurs in February (between January and May), David receives two supplemental tax bills. His local tax rate is 1.05%.
| Step | Result |
|---|---|
| Value of new construction | $95,000 |
| Annual supplemental tax ($95,000 × 1.05%) | $997.50 |
| Bill #1 proration factor (March 1 = .33) | .33 |
| Bill #1 amount (remainder of current fiscal year) | $329.18 |
| Bill #2 (full next fiscal year, July 1 – June 30) | $997.50 |
David’s existing base year value on the rest of his home stays the same. Only the newly constructed portion gets a new base year value. David should verify that the assessor valued only the new addition — not the entire home. If the assessor incorrectly reappraised the whole property, David has grounds for an appeal.
Scenario 3: The Nguyens Buy Below Prior Assessed Value
The Nguyen family purchases a home in November 2025 for $420,000. The prior owner’s Prop 13 assessed value was $485,000 (this can happen when a long-time owner’s base year value, after years of 2% annual increases, exceeds current market value due to a market downturn). The net supplemental assessment is negative.
| Step | Result |
|---|---|
| New base year value (purchase price) | $420,000 |
| Minus prior assessed value | $485,000 |
| Net supplemental assessment | −$65,000 |
| Annual tax decrease ($65,000 × 1.1%) | $715 |
| Proration factor (December 1 = .58) | .58 |
| Nguyen family’s supplemental refund | $414.70 |
The Sacramento County Assessor’s Office confirms that when a net supplemental assessment is negative, the auditor-controller issues a refund — not a bill. A critical detail: the supplemental refund cannot be used as a credit toward the existing annual tax bill. The Nguyens must still pay their regular property tax bill in full, and the refund comes separately.
Your Five Options When You Get a Notice
Option 1: Pay the Supplemental Tax Bill
The most straightforward option. Once the supplemental tax bill arrives (after the assessment notice), you pay it by the deadlines printed on the bill. Supplemental tax bills typically have two installments. If you miss a payment, penalties apply — and unlike annual bills, your lender will not receive a copy of the supplemental bill. You are personally responsible for paying it even if you have an impound/escrow account.
Option 2: Contact the County Assessor
Before doing anything formal, call or visit the assessor’s office. The staff can explain how your value was determined, review information you provide, and potentially correct errors without a formal appeal. Common errors include wrong square footage, incorrect property characteristics, or an inaccurate sale price. If the assessor’s office finds a mistake, they can reduce the value administratively.
Option 3: File a Formal Assessment Appeal
If you believe the assessed value is too high and the assessor won’t agree, you can file Form BOE-305-AH with the clerk of the Assessment Appeals Board in your county. You must file within 60 days of the mailing date on the notice (or postmark date, whichever is later). Some counties give you 60 days from the supplemental tax bill instead — check with your local clerk.
Option 4: Apply for a Homeowner’s Exemption
If the property is your primary residence and no homeowner’s exemption was already in place, you can apply for the $7,000 exemption when you receive the supplemental notice. This reduces your taxable value by $7,000, which saves roughly $70 per year at the base 1% tax rate. You must occupy the home within 90 days of purchase to qualify. The exemption is prorated on the supplemental assessment from the purchase date through June 30.
Option 5: Claim a Refund
If your new assessed value is lower than the prior value, you don’t owe anything — the county owes you. The Yolo County Assessor’s Office notes that a supplemental refund is automatically issued when the net supplemental assessment is negative. You don’t need to file a special claim for the refund in most counties, but you should verify the amount is correct.
The 60-Day Deadline That Can Destroy Your Appeal Rights
The single most important deadline in the supplemental assessment process is the 60-day appeal window. Under California law, you must file your appeal within 60 days of the date printed on the notice or its postmark date, whichever is later. This deadline is firm — the Assessment Appeals Board cannot extend it, and no exception exists for “I didn’t understand the notice” or “I was out of town.”
If you miss the 60-day window, your supplemental assessment becomes final. You can still file an appeal later — but only during the regular filing period (July 2 through September 15, or November 30 depending on your county) when the property’s value first appears on the regular assessment roll. The catch: at that point, you can only appeal the new base year value on the regular roll, not the supplemental assessment itself. You lose the ability to get a refund or reduction on the supplemental tax already paid.
| If You File Within 60 Days | If You Miss the 60-Day Window |
|---|---|
| You can challenge the supplemental assessment and the new base year value | You can only challenge the new base year value on the regular roll |
| A successful appeal gives you relief on both the supplemental tax and future taxes | A successful appeal only reduces future taxes — the supplemental tax is final |
| You preserve all rights | You permanently lose the right to a supplemental tax refund for that event |
Step-by-Step: Filing Form BOE-305-AH
Form BOE-305-AH is the official Assessment Appeal Application used across all 58 California counties. You must use the version issued by your county — a generic form from another county will be rejected. Many counties offer the form for download on the clerk of the board’s website, and some allow online filing.
Section 1: Applicant’s Information
Enter the property owner’s name, mailing address, phone number, and email. If you are a person with a direct economic interest in the property taxes (like a lessee responsible for property taxes), you can file as the affected party. A spouse, parent, child, or domestic partner may also sign and file on the owner’s behalf without a written authorization.
Section 2: Agent or Representative Information
If you hire an attorney or a property tax consultant to represent you, their information goes here. A written Authorization of Agent must be attached unless the agent is a California-licensed attorney. The authorization must include the date executed, the specific parcels covered, and a statement that the agent is authorized to file in the calendar year of the application.
Section 3: Property Identification
Enter the Assessor’s Parcel Number (APN) from your tax bill or assessment notice. Include the property address. Check the box that describes the property type — owner-occupied single-family residence, multi-family, commercial, etc. Also indicate whether the property is your principal place of residence.
Section 4: Value — The Most Critical Section
This section has two columns. Column A is the assessor’s value on the roll (copy this directly from your notice). Column B is your opinion of the property’s value. You must enter a number in Column B — if you leave it blank, the application is deemed incomplete and returned. This is where many applicants make a costly error. Your opinion of value should be supported by evidence such as comparable sales data.
Section 5: Type of Assessment Being Appealed
Check “Supplemental Assessment” if you are filing within 60 days of the notice. If you are filing after the 60-day window during the regular filing period, check “Regular Assessment” instead. You must also write the roll year being appealed and attach a copy of the supplemental assessment notice. Some counties require separate applications if one supplemental event affects two roll years.
Section 6: Reason for Filing
Check the box that matches your reason. For most supplemental appeals, you will check either “The market value based upon a change in ownership is less than the assessor’s value” or “No change in ownership occurred.” You can attach a brief written explanation. If you believe the assessor valued new construction incorrectly, check the new construction box.
Section 7: Written Findings of Fact
You may request that the board provide a written summary of the facts and evidence it used to reach its decision. This is important if you lose and want to appeal to superior court. You must request findings of fact before the hearing begins.
Section 8: Claim for Refund
Check “Yes” if you want the application to double as a refund claim. This means if the board rules in your favor, the county processes your refund automatically. Check “No” if you might want to file an action in superior court later — checking “yes” shortens the court filing deadline to six months from the board’s decision.
Signature
Sign the application under penalty of perjury. Use blue ink for paper filings. If your county allows online filing, follow their authentication process (usually an assigned personal identification number).
What Happens at Your Assessment Appeal Hearing
After you file, the law requires the clerk to notify you at least 45 days before your hearing date. At the hearing, you present your evidence first, and then the county assessor (or a representative) presents theirs. The board can lower, raise, or confirm the assessed value based on the evidence — which means filing an appeal is not risk-free.
The burden of proof falls on different parties depending on the situation. For a decline in value appeal, you must prove the property’s market value is lower than the assessed value. For a base year value appeal (the most common supplemental assessment challenge), the assessor has the initial burden of showing the value is correct if you purchased the property at arm’s length.
What Counts as Admissible Evidence
The most powerful evidence in a residential appeal is comparable sales — recent sales of similar homes in your area. You should gather data on 3 to 5 comparable properties that sold near the date of your purchase or new construction event. The appeals board cannot consider information attached to your application — you must present it live at the hearing. Depositions are not admissible.
Other types of evidence include a written appraisal from a licensed appraiser, oral testimony, photographs showing property condition issues, and written materials supporting your value opinion. The assessor’s office will also present comparable sales and may challenge yours. Point out specific differences between the assessor’s comparables and your property — but don’t rely only on poking holes in the assessor’s case. You must prove your own value to win.
Mistakes to Avoid with a Supplemental Assessment
Mistake #1: Ignoring the Notice Because You Think It’s a Duplicate
Many homeowners receive the Notice of Supplemental Assessment and assume it’s a duplicate of their annual assessment notice. It is not. Ignoring it means you miss the 60-day appeal window and lose the right to challenge the supplemental value.
Mistake #2: Assuming Your Lender Will Pay the Supplemental Bill
Your mortgage lender does not receive supplemental tax bills — even if they pay your regular property taxes through escrow. Supplemental bills go directly to you, the property owner. If you don’t pay because you assumed your lender would handle it, penalties cannot be excused under California law.
Mistake #3: Filing the Appeal After the 60-Day Deadline
The clerk of the board will reject a late application. There are no extensions, no exceptions for hardship, and no “grace period.” If you received the notice on Day 1, you must file by Day 60 at the latest. Count from the mailing date or postmark date printed on the notice, whichever is later.
Mistake #4: Leaving Column B (Your Opinion of Value) Blank
If you submit Form BOE-305-AH without entering your opinion of value in Column B, the application is returned as incomplete. By the time you resubmit, the 60-day deadline may have passed — killing your appeal.
Mistake #5: Using a Neighbor’s Lower Assessment as Evidence
A common instinct is to tell the board that your neighbor’s nicer home has a lower assessment. The board will not allow this argument. A lower assessment on another property could mean that property is under-assessed — it does not prove yours is over-assessed. Only comparable sales data matters.
Mistake #6: Not Paying While You Appeal
You are required to pay your property taxes on time, even if your appeal is pending. Failure to pay results in penalties and interest that cannot be waived regardless of your appeal outcome. If you win the appeal, the county issues a refund.
Mistake #7: Trying to Reduce Your Tax Rate Instead of Your Assessed Value
The Assessment Appeals Board has no power to change the tax rate, waive penalties, or grant exemptions. It can only adjust the assessed value. If your issue is with the tax rate or a specific bond measure, the appeals board is the wrong venue.
Do’s and Don’ts for Handling Your Notice
| Do | Don’t |
|---|---|
| Do open and read the notice immediately — your 60-day clock is running | Don’t assume it’s junk mail or a duplicate of your annual notice |
| Do verify the assessed value against your actual purchase price or construction cost | Don’t accept the assessed value without checking for errors in property details |
| Do call the assessor’s office before filing a formal appeal to discuss errors | Don’t skip the informal discussion — many issues get resolved without an appeal |
| Do file Form BOE-305-AH well before the 60-day deadline | Don’t wait until the last day — mailing delays or clerical issues can cause rejection |
| Do gather 3–5 comparable sales to support your opinion of value | Don’t rely on Zillow estimates, Redfin “Zestimates,” or unsupported opinions |
| Do pay your supplemental tax bill on time even if you are appealing | Don’t withhold payment thinking the appeal pauses your obligation |
| Do apply for the homeowner’s exemption if the property is your primary residence | Don’t assume the exemption transfers from the previous owner — it does not |
| Do check whether you qualify for a parent-to-child or other reassessment exclusion | Don’t assume all family transfers are exempt — Proposition 19 changed the rules significantly |
The Upside and Downside of Filing an Appeal
| Pros of Filing an Appeal | Cons of Filing an Appeal |
|---|---|
| You could save thousands of dollars if the assessed value is reduced | The board can increase the assessed value based on evidence — your taxes could go up |
| A successful appeal reduces both the supplemental tax and your future base year value | The process takes time — hearings can be scheduled months after filing |
| Filing preserves your legal rights, including the ability to go to superior court | You may need to hire an appraiser or attorney, which costs money |
| The appeals board is independent from the assessor — it’s a neutral review | You must still pay your taxes in full while the appeal is pending |
| You can negotiate a stipulated value with the assessor before the hearing | If the assessor signals a higher value, some counties won’t let you withdraw the appeal |
How Multiple Supplemental Events Stack Up
If you complete multiple construction projects in the same year, each one generates its own supplemental assessment. The Board of Equalization gives an example: you finish a pool in March (two supplemental bills), add a garage in April (two more bills), and enclose a patio in May (two more bills). That’s six supplemental tax bills in addition to your annual bill.
The total property tax across all these bills cannot exceed what you would have owed if the full combined value had appeared on a single annual tax bill from the start. The proration system means you typically pay slightly less than the full annual amount across all supplemental bills for a given fiscal year.
When a property sells twice in the same fiscal year, the supplemental assessments for both transactions get intertwined. Under Revenue and Taxation Code §75.54, the county prorates the first buyer’s supplemental tax between the first and second buyer based on days of ownership. The second buyer may receive a supplemental bill that was originally generated by the first buyer’s purchase.
Key Entities and Who Does What
Understanding which office handles each part of the supplemental assessment process helps you contact the right people at the right time.
| Entity | Role in the Process |
|---|---|
| County Assessor | Determines the new market value, calculates the net supplemental assessment, and mails the Notice of Supplemental Assessment |
| County Auditor-Controller | Applies the tax rate and proration factor to calculate the actual tax owed (or refund due) |
| County Tax Collector | Mails the supplemental tax bill and collects payment |
| Assessment Appeals Board (AAB) | Hears your formal appeal and decides whether to lower, raise, or confirm the assessed value |
| Clerk of the Board | Processes your BOE-305-AH filing, schedules your hearing, and enforces deadlines |
| California State Board of Equalization (BOE) | Oversees the statewide property tax system, publishes rules and guidance, and provides the Taxpayers’ Rights Advocate |
The Taxpayers’ Rights Advocate at the Board of Equalization is a resource if you cannot resolve issues through your county. Their office helps property owners navigate disputes that other levels have not resolved. You can reach them at the State Board of Equalization in Sacramento.
Relevant Legal Precedent and Rulings
California courts and the Board of Equalization have issued rulings that shape how supplemental assessments work. Under Annotated Legal Opinion 790.0032, when the same property has two changes in ownership and the first buyer did not timely appeal the first supplemental assessment, the second buyer has no right to appeal any portion of the first supplemental assessment. The term “the supplemental assessment” in Revenue and Taxation Code §75.31(c) refers only to the second supplemental assessment resulting from the second change in ownership.
The statute of limitations for supplemental assessments is governed by Revenue and Taxation Code §75.11(d). This section sets specific time limits for when the assessor can add a supplemental assessment to the roll. Under Opinion 790.0300, supplemental assessments are valid if made within the statute of limitations in effect at the time the assessment is made — even if they would have been barred under a previous version of the statute.
Revenue and Taxation Code §75.21(a) provides that exemptions “shall be applied” to supplemental assessments. Under Opinion 790.0077, exemptions should not be added to negative supplemental assessments, because doing so would increase the refund rather than offset the assessment. The word “applied” means reducing a positive amount, not augmenting a negative one.
Exclusions from Reassessment You Should Know About
Not every change in ownership triggers a full reassessment. California law provides specific exclusions that can prevent or limit a supplemental assessment. Filing the correct claim form with the assessor is required — you don’t receive these exclusions automatically.
Proposition 19 (effective February 16, 2021, for parent-child transfers and April 1, 2021, for base year value transfers) replaced the old Proposition 58/193 rules. Under Prop 19, a parent can transfer a primary residence to a child without reassessment only if the child uses it as their own primary residence and the property’s market value does not exceed the parent’s assessed value by more than $1 million. Any excess over $1 million gets partially reassessed.
Interspousal transfers (between spouses or registered domestic partners, including transfers upon divorce) are fully excluded from reassessment. Transfers into and out of revocable trusts where the transferor is a beneficiary are also excluded. Co-tenancy transfers where a co-owner’s proportional interest does not change are another common exclusion.
FAQs
Can I pay my supplemental tax bill in installments?
No. Each installment must be paid in full by its due date. A partial payment will be returned with notice of the balance due, and penalties apply if the full amount is not received on time.
Does my lender pay the supplemental tax bill from escrow?
No. Supplemental bills are mailed directly to the property owner. Your lender does not receive a copy, even if they pay your annual taxes through impound.
Can the appeals board raise my assessed value if I appeal?
Yes. The board can increase, decrease, or confirm the assessed value based on evidence presented at the hearing.
Is the supplemental tax bill separate from my annual tax bill?
Yes. The supplemental bill is in addition to the annual property tax bill, and both must be paid by their respective deadlines.
Can I appeal a supplemental assessment after the 60-day deadline?
Yes, but only during the regular filing period (July 2–September 15 or November 30). You can challenge only the base year value on the regular roll, not the supplemental assessment itself.
Do penalties get waived if I didn’t know about the bill?
No. California law does not allow penalties to be excused because you were unaware of the supplemental tax bill or because of a misunderstanding with your lender.
Will I get a refund if my new value is lower than the old value?
Yes. A negative supplemental assessment generates a refund check from the county auditor-controller, prorated for the remaining months of the fiscal year.
Can I apply the refund toward my annual property tax bill?
No. A supplemental refund cannot be credited toward the existing annual tax bill. The annual bill must still be paid in full.
Does the homeowner’s exemption apply to supplemental assessments?
Yes, if the property is your primary residence and no exemption was already in place. The full $7,000 exemption is prorated from the purchase date through June 30.
Are supplemental assessments unique to California?
Yes. California’s supplemental roll system, created by Revenue and Taxation Code §75 et seq., is specific to the state’s Proposition 13 property tax framework. Other states do not use this system.
Can I file one appeal for multiple supplemental assessments?
No. A separate BOE-305-AH application must be filed for each parcel and, in some counties, for each roll year affected by the supplemental event.
What if I believe no change in ownership actually occurred?
Yes, you can appeal on those grounds. Check the “no change in ownership occurred” box on the BOE-305-AH form and provide supporting evidence at the hearing.
Do I need a lawyer to file an appeal?
No. Property owners regularly represent themselves at Assessment Appeals Board hearings. An attorney or property tax consultant is optional but can improve outcomes in complex cases.
How long does the appeal process take?
It varies by county — typically 3 to 12 months from filing to hearing. The clerk must give you at least 45 days’ notice before your hearing date.
Can I negotiate with the assessor after filing an appeal?
Yes. You and the assessor can reach a written agreement (called a “stipulation”) at any time before the hearing. The appeals board can accept or reject the stipulation.
Related reading
- How To Avoid Property Tax Reassessment In California (Prop. 19)? + FAQs
- How Can I Appeal My Property Tax Assessment? + FAQs
- How Much Can My Property Tax Go Up After a Remodel? + FAQs
- How to Write a Property Tax Appeal Letter? + FAQs
- Can You Write Off Special Assessment on Taxes?(w/Examples) + FAQs
- Are Supplemental Taxes Paid Every Year? (w/Examples) + FAQs
- How to Fill Out California Form CIV-010 (w/Examples) + FAQs