Prop 13 California reassessment rules when your home sells

Last updated 2026-07-09

What does Prop 13 actually say about reassessment when a home sells?

A home sale resets your property tax clock in California. The sale price becomes your new base year value, and everything the previous owner had locked in disappears the day the deed records.

California's Proposition 13, passed by voters in June 1978 and codified at Article XIII A of the California Constitution, does two things at once. First, it caps the annual property tax rate at 1% of assessed value (plus voter-approved bond rates, which run roughly 0.2% to 0.3% statewide but vary a lot by jurisdiction). Second, it freezes the assessed value at whatever the property was worth in 1975, or at the purchase price the last time it changed hands, and then allows that base year value to grow no more than 2% per year until the property changes ownership again or new construction occurs. ^[1]

So when a home sells, the county assessor resets the clock. The sale price becomes the new base year value. The 2% annual cap starts fresh. Buyers often walk into a tax bill far higher than what the seller paid, because the seller may have owned for 20 or 30 years with an assessed value still stuck near a 1990s purchase price.

The California State Board of Equalization (BOE) administers the rules that all 58 county assessors follow. The core statute is Revenue and Taxation Code sections 60 through 69.6. ^[2]

What counts as a 'change in ownership' that triggers reassessment?

A "change in ownership" is any transfer of a real, present interest in property with a value roughly equal to full ownership. Sales are the obvious case, but so are many transfers people never expect, including some trust changes and corporate control shifts.

Under Revenue and Taxation Code section 60, a change in ownership is "a transfer of a present interest in real property, including the beneficial use thereof, the value of which is substantially equal to the value of the fee interest." That definition is broad on purpose, and the BOE has spent decades issuing guidance on what triggers it. ^[2]

An arm's-length sale to an unrelated buyer almost always triggers full reassessment. But these also matter:

• Transferring the property into a revocable living trust where you're the sole beneficiary does NOT trigger reassessment. The property is still "yours" for reassessment purposes.
• Transferring into an irrevocable trust generally DOES trigger reassessment because you've given up control and beneficial interest.
• Adding someone to title (say, a spouse) does not automatically trigger reassessment if they hold less than 50% interest in some circumstances, but this gets complicated fast.
• Corporate entity transfers can trigger reassessment when a "change in control" occurs, meaning one person or entity ends up with more than 50% of the shares or voting rights.
• Death and inheritance: a property passing to a child or grandchild does NOT automatically trigger reassessment if the correct exclusion forms are filed on time (more on that below).

If you're unsure whether a specific transfer triggers reassessment, the county assessor's office can give you a written preliminary determination before the transfer happens. That's worth doing for anything other than a plain sale.

How does the assessor calculate the new assessed value after a sale?

The purchase price is the starting point, but "purchase price" means more than the number on the grant deed. The assessor uses the full consideration paid, which can include assumed debt, personal property allocations, and sometimes lease arrangements. ^[2]

Pay $900,000 for a house and your new taxable value is generally $900,000. Your base year tax at the 1% rate is $9,000, before any local bonds or special assessments. Add those and you're usually looking at 1.1% to 1.4% of assessed value in most California counties.

County	Approx. effective tax rate (2023)	Notes
Los Angeles	1.16% to 1.25%	Varies by city/school district [3]
Santa Clara	1.10% to 1.20%	Lower bond load than many [4]
San Diego	1.05% to 1.20%	Varies by district
Sacramento	1.05% to 1.15%	Varies by district
Alameda	1.15% to 1.30%	Higher Mello-Roos exposure

After closing, the assessor has no statutory deadline to complete the reassessment, but most counties process sales within one to three annual tax rolls following the sale date. The base year value is established as of the date the deed recorded, and the new bill applies to the full fiscal year in which ownership changed (July 1 to June 30 in California). ^[2]

The first bill after a sale often comes as a "supplemental assessment," a separate bill covering just the period between your close of escrow and the end of the current tax year. Buyers who don't plan for this get surprised. A supplemental can land months after closing and cover six months of increased taxes that nobody set aside in escrow.

How is the supplemental assessment calculated and when does it arrive?

A supplemental bill charges you the tax on the jump in value, prorated for the part of the fiscal year left after you closed. It arrives separately from your annual bill, often 6 to 18 months after recording, and your mortgage impound account usually won't cover it.

California Revenue and Taxation Code section 75 et seq. governs supplemental assessments. When a sale closes mid-year, the assessor calculates the difference between the old assessed value and the new purchase price, prorates it for the fraction of the fiscal year remaining after the sale date, and sends a separate bill for that amount. ^[8]

Close on October 1 and you have nine months left in the fiscal year (October through June). The supplemental bill covers that nine-month portion at the new rate. If the old assessed value was $300,000 and you paid $900,000, the assessor is taxing an additional $600,000 of value for nine months. At a 1.2% effective rate, that supplemental runs about $5,400.

The assessor typically mails the supplemental bill within 6 to 18 months of recording. It's separate from your regular annual bill, and many first-time California buyers miss it entirely. A lender that collects impound payments generally won't have this covered, because impounds are based on the prior assessed value.

Close between January 1 and May 31 and you may receive TWO supplemental bills: one for the partial year and one for the following full year, because the change straddles two tax rolls. ^[8]

For Los Angeles County property tax questions specifically, the LA County Assessor publishes a supplemental assessment calculator on its website that walks you through the math before your bill arrives. Worth bookmarking after any purchase. Homeowners sorting out Santa Clara property tax bills can find supplemental estimators through the Santa Clara County Assessor's portal.

What transfers are excluded from reassessment under Prop 13?

Several transfers can change hands without a full reassessment: spousal transfers, qualifying parent-child and grandparent-grandchild transfers, moves into a revocable trust, and the senior base year value transfer. None of these happen automatically. You apply, and most carry hard deadlines. ^[5]

Parent to child (Prop 19, effective Feb 16, 2021) Proposition 19, approved by California voters in November 2020, tightened the old parent-child exclusion sharply. Before Prop 19, you could transfer any real property to a child without reassessment. Now, for transfers on or after February 16, 2021, the exclusion applies only to a primary residence, and only if the child moves in and makes it their primary residence within one year. The excluded value is capped at the parent's assessed value plus $1,000,000 (adjusted annually for inflation). ^[5]

If the child doesn't move in, or the property is a rental or vacation home, the full reassessment hits. Many families didn't see this coming.

Grandparent to grandchild Same Prop 19 rules apply. The property must be a primary residence transferred to a grandchild, and the grandchild must move in within one year. Available only when both of the grandchild's parents are deceased. ^[5]

Spousal transfers Transfers between spouses do not trigger reassessment. This includes transfers at death, during divorce, and gifts between spouses. No application is technically required, but filing the BOE parent-child exclusion form still protects the record. ^[5]

Transfers between registered domestic partners Same treatment as spouses under California Family Code. ^[5]

Transfers into or out of a living trust No reassessment if you're transferring into a revocable trust where you're the trustee and sole current beneficiary. When the trust becomes irrevocable (typically at death) and the property passes to beneficiaries, the parent-child or grandparent-grandchild exclusion can still apply if the criteria are met. ^[5]

Disabled persons and senior citizens: the base year value transfer (Props 60/90/19) Prop 19 replaced the old Props 60 and 90 with an expanded but still limited benefit. Homeowners who are 55 or older, severely disabled, or victims of a Governor-declared disaster can transfer their current base year value to a replacement home of any value anywhere in California. Before Prop 19 (effective April 1, 2021), this was once-in-a-lifetime and restricted by price. Now you can use it up to three times. ^[5]

Filing the right exclusion form with the county assessor on time is the whole game. The deadlines are strict.

What is the deadline to file a reassessment exclusion, and what happens if you miss it?

For parent-child and grandparent-grandchild exclusions, file within three years of the transfer date, or before the property is sold, whichever comes first. File after that window but before the assessor mails a notice of reassessment and you can still get the exclusion. Once that notice goes out, you're generally locked out. ^[5]

For the base year value transfer (senior or disabled), you file after purchasing or newly constructing the replacement property. There's no hard statutory deadline for the replacement home claim, but county assessors process it faster if you file within one year.

Missing the parent-child deadline costs more than the exclusion going forward. The assessor will reassess back to the transfer date and send supplemental bills for every intervening year at the higher value, plus interest in some cases.

The BOE parent-child and grandparent-grandchild exclusion claim (form BOE-58-AH) and the senior/disabled base year value transfer claim (form BOE-19-B) are both available from your county assessor or the BOE website. ^[5]

If you're dealing with a trust, some counties also require a Preliminary Change of Ownership Report (PCOR) at the time of transfer. That's a different form from the exclusion claim, and filing the PCOR wrong can trigger reassessment by accident.

Can the assessed value after a sale be lower than the purchase price?

Yes, and this option is genuinely underused. If your property's market value falls below its base year assessed value on any January 1 assessment date, you can apply for a temporary reduction. This is a Prop 8 review, named after a 1978 ballot measure that added the provision to Revenue and Taxation Code section 51. ^[6]

Assessors are supposed to enroll the lower of (a) the base year value adjusted for the 2% annual cap or (b) the current market value as of January 1. In practice, they don't always do this automatically when markets drop. You may need to ask.

During the 2008 to 2012 crash, millions of California homeowners had their assessed values temporarily cut below their original purchase price. When the market recovered, assessors restored those values at up to the full 2% annual cap, plus catch-up, until they reached the original adjusted base year value. BOE guidance confirms this, which means values can bounce back faster than 2% after a Prop 8 reduction. ^[6]

Buy in a rising market that then drops, and a Prop 8 application can get you real tax relief within a year. The application deadline usually falls in late summer or early fall before the January 1 assessment date. Each county sets its own, so check with your assessor.

A Prop 8 review is not the same as an appeal. If you think the assessor got your new base year value flat wrong after a sale, you appeal instead. An appeal of base year value (BYV) has a stricter window: you generally have four years from the date the assessor first enrolled the value, and the form is BOE-305-AH. ^[7]

How does Prop 19 change things compared to the old Prop 13 rules?

People conflate "Prop 13" with the current rules, when Prop 19 (November 2020) rewrote large parts of what most people thought they knew. For an ordinary arm's-length sale, nothing changed. For family transfers, almost everything did. ^[5]

The original Prop 13 still works the same way at a straight sale: sale price equals new base year value, 1% cap, 2% annual inflation cap. That's the law.

What Prop 19 changed:

1. Parent-child and grandparent-grandchild exclusions. Narrowed sharply, as described above. 2. The senior/disabled base year value transfer. Expanded: now statewide (more than the same or a lower-value county), up to three transfers (not one), and replacement homes of any value (with a partial exclusion when the new home costs more). 3. Revenue from the narrowed parent-child exclusion funds wildfire response and county assessor operations. ^[11]

For families planning estate transfers, the practical takeaway is blunt: the old move of inheriting the family vacation home or rental without reassessment is gone. Plan with an estate attorney before transferring, not after.

For arm's-length buyers, none of this matters. You pay, you get reassessed to purchase price, and you're on the 2% escalator from there.

How much will my property taxes increase after buying a California home?

It depends on how long the seller owned the home and how far prices climbed since they bought. The longer they held, the bigger your jump. On a long-held home in a hot market, the gap between the seller's bill and yours can top $15,000 a year.

Say the seller bought in 1995 for $180,000 and you're paying $950,000. Their assessed value might have grown to roughly $300,000 to $350,000 over 30 years at 2% annually. Their annual tax bill at a 1.2% effective rate: around $3,600 to $4,200. Your bill at the same rate: $11,400. That's a $7,000 to $7,800 jump per year for the same house.

In markets like San Jose or Los Angeles, where prices compounded over 30 to 40 years, the gap between seller and buyer can reach $15,000 to $25,000 per year on a single-family home. This is the defining financial feature of California real estate, and it's why many long-term owners refuse to sell.

The 2% cap matters more the longer you own. In year one, it barely moves your bill. In year 30, your base year value has only doubled. Someone buying at the same price today still pays roughly what you paid in year one, while you pay far less. That's the lock-in effect that feeds California's housing supply problem.

Want a precise estimate before you buy? LA County and Santa Clara County both publish online tax calculators that pull actual assessed values and bond rates by parcel. They beat any rule of thumb.

What if the assessor reassesses at a value different from what I paid?

Assessors are generally required to use the full purchase price as the base year value. A few situations push them off it:

• If the sale included significant personal property (appliances, furniture, business equipment), the assessor may allocate part of the purchase price to personal property, which is taxed differently. Spell out separate values for personal property in your purchase contract, or the assessor will estimate.
• If the sale was between related parties at a non-market price, the assessor may reject the sale price and use a market value appraisal instead. That usually hurts the buyer when market value is higher than the sale price.
• If the assessor believes the sale wasn't a market-rate transaction (a distressed sale, a sale under duress, or one with special financing), they can look past the price.

If the assessor enrolls a value higher than what you paid, you can appeal. For most California counties, the deadline to appeal the base year value is either September 15 of the assessment year or 60 days from the date the assessor mailed the notice of new assessed value, whichever is later. ^[7] Some counties run extended periods. Check your county's Assessment Appeals Board.

The la-county property tax appeal deadline is September 15 for most properties, but you get 60 days from a change-in-ownership supplemental notice. Miss it and you wait another full cycle.

Building a real appeal with comparable sales is entirely doable yourself. TaxFightBack's appeal kit walks you through gathering comps, completing county forms, and presenting your case without hiring a contingency firm that takes 25% to 40% of any savings.

For guidance in the biggest California markets, see our guides on la county property tax and santa clara property tax.

Are there any other exclusions or situations that affect reassessment?

A handful of less common situations change the math:

New construction vs. sale. Only the newly built portion gets reassessed when you permit an addition or major renovation. The existing structure keeps its base year value. ^[1]

Disaster victims. If your home is destroyed in a disaster, California Revenue and Taxation Code section 69 lets the base year value transfer to a replacement property of comparable or lesser value in the same county (or any county that has adopted the ordinance). ^[2]

Original transferor rule. If a property was originally transferred to a corporation or other entity and the original transferor later reacquires it, that reacquisition may not trigger reassessment under specific conditions. Niche, but it matters for small business owners who put property into an LLC.

Cotenancy exclusion. Transfers between cotenants who together own 100% of the property don't trigger reassessment if no money changes hands and the proportional ownership stays the same.

Builder's inventory exclusion. Property a developer builds and holds for sale as inventory is treated differently. The developer generally isn't reassessed at "sale" until a third party buys the unit.

These are real but rare. If one applies to your property, a consultation with a California property tax attorney or CPA before recording the deed is money well spent.

Frequently asked questions

Does selling a home always trigger a full reassessment in California?

Almost always, yes. An arm's-length sale between unrelated parties virtually always triggers full reassessment to the purchase price under Revenue and Taxation Code section 60. The exceptions are narrow: certain family transfers with valid exclusion claims filed on time, transfers into revocable living trusts where you remain the trustee and sole beneficiary, and a few other limited situations in sections 62 through 69 of the code.

When does the county assessor send the new tax bill after a sale?

Expect two bills: your regular annual bill (based on the new base year value for the full fiscal year) and a separate supplemental assessment bill covering the period from your close of escrow to the end of the fiscal year. The supplemental typically arrives 6 to 18 months after closing. Close between January 1 and May 31 and you may get two supplemental bills. Budget for both.

Can I transfer my home to my kids without triggering Prop 13 reassessment?

Only under strict Prop 19 rules that took effect February 16, 2021. The property must be your primary residence, and your child must move in and claim it as their primary residence within one year of the transfer. Investment properties, vacation homes, and second homes no longer qualify. The old unlimited parent-child exclusion is gone. File BOE Form 58-AH with your county assessor within three years of the transfer.

What is a supplemental property tax bill and how is it different from a regular bill?

A supplemental bill covers the prorated tax difference between the old assessed value and your new purchase price, for the portion of the fiscal year after you closed. It's a one-time charge (or two if you straddle two tax years), separate from your ongoing annual bill. It's authorized by Revenue and Taxation Code section 75 and mailed by the county tax collector, not necessarily by your mortgage servicer.

What is the Prop 19 base year value transfer for seniors and how does it work?

Homeowners who are 55 or older, severely disabled, or disaster victims can transfer their existing Prop 13 base year value to a replacement home anywhere in California. Prop 19 expanded this to be statewide, usable up to three times, and available for a replacement home of any price (with a partial exclusion if the new home costs more). It took effect April 1, 2021, and replaced the older Props 60 and 90. File BOE Form 19-B after purchase.

Does putting my home in a trust trigger reassessment?

Transferring to a revocable living trust where you're the trustee and sole current beneficiary does not trigger reassessment. Transferring to an irrevocable trust generally does, because you give up beneficial interest. When a revocable trust becomes irrevocable at death and assets pass to children, the parent-child exclusion may apply if Prop 19 criteria are met and BOE Form 58-AH is filed within three years.

Can I appeal my assessed value after buying a California home?

Yes. If the assessor enrolls a base year value you believe is too high, you can appeal to the county Assessment Appeals Board. The deadline is typically September 15 of the assessment year, or 60 days from the mailing of a supplemental notice, whichever is later. You'll need evidence: comparable sales near your purchase date, inspection reports showing property defects, or appraisals. File on the correct county form before the deadline; late filings are rejected.

What happens to property taxes when you inherit a California home after 2021?

Under Prop 19, inheriting a California home no longer comes with an automatic reassessment exclusion. The exclusion now requires the property to be the parent's (or grandparent's) primary residence and the inheriting child (or grandchild) to move in within one year and claim it as their own primary residence. If those conditions aren't met, the property is fully reassessed to current market value as of the date of transfer.

What is a Prop 8 review and should I request one after buying?

Prop 8 (Revenue and Taxation Code section 51) requires assessors to enroll the lower of the base year adjusted value or current market value. If market values drop after you buy, you can request a temporary assessment reduction. There's no automatic trigger; you usually have to apply. If granted, the value can be restored in future years at faster than 2% annually until it returns to the original adjusted base year value.

Are there any situations where a sale does NOT trigger reassessment?

A few. Transfers between spouses and registered domestic partners are excluded. Qualifying parent-child and grandparent-grandchild transfers with Prop 19 criteria met and forms filed in time are excluded. Transfers into a qualifying revocable living trust are excluded. The cotenancy exclusion covers proportional transfers between existing co-owners. Corporate entity transfers that don't leave a single party controlling more than 50% also may not trigger reassessment.

How does Mello-Roos affect my tax bill after buying in California?

Mello-Roos Community Facilities Districts (authorized by the Mello-Roos Community Facilities Act of 1982) impose special assessments on top of the 1% Prop 13 rate. They fund schools, infrastructure, and emergency services in newer developments and are tied to the parcel, not the assessed value. They don't change with reassessment, but they can add 0.2% to over 1% to your effective rate. Check the PCOR and title reports before closing to see if a Mello-Roos lien applies.

Does a short sale or foreclosure affect how the assessor sets the new base year value?

The assessor is supposed to use the actual sale price as the base year value. But if a short sale price is far below market value due to distressed circumstances, the assessor may question whether it's a valid open-market transaction and substitute their own market value estimate. That can produce a higher assessed value than you paid. If it happens, you can appeal using comparable arm's-length sales from the same period.

Can adding someone to a deed trigger reassessment?

It can. Adding a non-spouse to title transfers a fractional ownership interest, which can count as a change in ownership for that fraction. Adding a child to your deed while you're alive typically triggers reassessment for their percentage, and it forfeits the step-up in cost basis they'd get at your death. Most estate attorneys advise against adding children to title for this reason; a trust is usually cleaner.

What is the difference between a Prop 8 review and a base year value appeal?

They fix two different problems. A Prop 8 review is a temporary reduction when current market value drops below your adjusted base year value; you apply each year the drop lasts, usually by a late-summer or early-fall deadline. A base year value appeal challenges the assessor's original valuation as wrong, using comparable sales, and you generally have four years from when the value was first enrolled to file BOE Form 305-AH.

Sources

1. California Constitution, Article XIII A (Proposition 13): Prop 13 caps the annual property tax rate at 1% of assessed value and limits annual increases in assessed value to 2% until the next change of ownership or new construction
2. California State Board of Equalization, Revenue and Taxation Code sections 60-69.6 (Change in Ownership): A change in ownership is defined as 'a transfer of a present interest in real property, including the beneficial use thereof, the value of which is substantially equal to the value of the fee interest'; sale triggers reassessment to purchase price
3. Los Angeles County Office of the Assessor: Los Angeles County effective property tax rates including bonds and special assessments range approximately 1.16% to 1.25% depending on city and school district
4. Santa Clara County Office of the Assessor: Santa Clara County effective property tax rates range approximately 1.10% to 1.20% of assessed value
5. California State Board of Equalization, Property Taxes home: Prop 19 effective February 16, 2021 narrowed the parent-child exclusion to primary residences only with a $1,000,000 value limit above the parent's assessed value, and expanded the senior base year value transfer to be statewide and usable up to three times; parent-child exclusion claim BOE-58-AH must be filed within three years of transfer
6. California State Board of Equalization, Property Taxes home (Prop 8 decline-in-value): Revenue and Taxation Code section 51 requires assessors to enroll the lower of the adjusted base year value or current market value; after a Prop 8 reduction, values can be restored faster than 2% annually until reaching the original adjusted base year value
7. California State Board of Equalization, Property Taxes home (Assessment Appeals, form BOE-305-AH): Taxpayers have four years from the date the assessor first enrolled the base year value to file a formal appeal; the typical county deadline is September 15 or 60 days from mailing of a supplemental assessment notice
8. California State Board of Equalization, Property Taxes home (Supplemental Assessments, Revenue and Taxation Code section 75): Supplemental assessments are prorated from the date of ownership change to the end of the fiscal year; buyers closing January 1 to May 31 may receive two supplemental bills
9. California Revenue and Taxation Code section 63.1 (Parent-Child Exclusion): Claim for reassessment exclusion for transfer between parent and child must be filed within three years of the date of transfer or before the property is sold, whichever comes first
10. California Revenue and Taxation Code section 69.5 (Base Year Value Transfer): BOE Form 19-B is the required application for the senior, severely disabled, or disaster victim base year value transfer under Prop 19
11. California Legislative Analyst's Office, Proposition 19 Analysis (2020): Prop 19 was estimated to reduce property tax revenues from the narrowed parent-child exclusion while generating revenue for wildfire response; it replaced Props 60 and 90 for the senior base year transfer effective April 1, 2021
12. Mello-Roos Community Facilities Act of 1982, California Government Code section 53311 et seq.: Mello-Roos districts can impose special taxes on parcels for infrastructure and services on top of the 1% Prop 13 rate, with effective additions commonly ranging from 0.2% to over 1% in newer California developments