Property Taxes
What determines your assessed value at purchase, why your first-year bills arrive in an unfamiliar order, and how Prop 19 changed inherited property in California.
California assesses property differently from almost every other state, and the difference is the reason two neighbours on the same street can pay wildly different tax bills on nearly identical houses. Proposition 13, passed in 1978, replaced annual market-value assessment with a base year value that is established when you buy and then grows slowly. The practical effect for a buyer is that the seller's current tax bill tells you almost nothing about what yours will be. Understanding the mechanism, rather than memorising a rate, is what lets you budget accurately in your first two years of ownership.
Proposition 19, effective in 2021, then rewrote the rules for keeping a low assessment inside a family and for carrying one to a new home. It narrowed what parents can pass to children without reassessment, and it widened the ability of homeowners aged fifty-five and over, severely disabled homeowners and disaster victims to take their existing assessment with them when they move. Both halves of that change have reshaped decisions in established Los Angeles neighbourhoods, where families have held property for decades and where the gap between assessed value and market value can be very large indeed.
This guide sets out the mechanics as published by the California State Board of Equalization and the Los Angeles County Treasurer and Tax Collector, with sources and dates named in the text. It is written to help you ask precise questions, not to answer your particular situation. Property tax outcomes turn on details of title, timing, occupancy and filings, and the cost of a wrong assumption is measured in decades of higher bills. Retain your own CPA and, where a trust, an entity or an inheritance is involved, a California estate or real property attorney before you rely on any of it.
The California State Board of Equalization publication California Property Tax: An Overview, dated March 2025, sets out the framework concisely. The ad valorem property tax rate is one per cent plus the rate necessary to fund local voter-approved bonded indebtedness. Assessed value is anchored to a base year value, defined as fair market value as of either the 1975 lien date or the date the property was purchased or newly constructed. Proposition 13 then generally limits annual increases in that base year value to no more than two per cent.
Two consequences follow. First, the longer a property is held, the further its assessed value can drift below its market value, because two per cent compounding rarely keeps pace with Los Angeles appreciation over twenty or thirty years. Second, that gap is not transferable to a buyer by ordinary purchase. The same publication is explicit that properties are reassessed to current market value only upon a change in ownership or completion of new construction. When you buy, you establish a new base year value at your purchase price, and the seller's decades of protection ends.
It is worth being precise about the one per cent figure, because it is the most commonly misquoted number in California real estate. One per cent is the ad valorem rate. Actual bills also carry voter-approved debt service and, in many areas, direct assessments and special district charges that are not calculated on assessed value at all. The total effective rate therefore varies by location and is always higher than one per cent. Owner-occupants who qualify may also claim the homeowners' exemption, which the Board describes as a seven thousand dollar reduction of taxable value on a qualifying principal residence.
A purchase is a change in ownership, so the county assessor establishes a new base year value based on market value as of the date ownership changed. What confuses most buyers is the timing. The annual secured tax bill for the fiscal year in progress was calculated on the prior owner's assessed value, and it does not change mid-year. Instead, the difference between the old assessment and yours is billed separately through a supplemental assessment, which the Board of Equalization describes as a prorated assessment reflecting the increase or decrease in assessed value resulting from the reappraisal.
The Los Angeles County Treasurer and Tax Collector explains the practical consequences. Supplemental bills follow reassessment after an ownership change or new construction, and a change occurring between January 1 and May 31 triggers two supplemental assessments and two bills, one for the remainder of that fiscal year and one for the following year. Processing generally takes about six months. Critically, the Treasurer and Tax Collector notes that lenders typically do not pay supplemental bills, which makes them the owner's direct responsibility even when an impound account is collecting for the regular bill.
That combination catches a remarkable number of otherwise careful buyers. The regular bill is paid by the servicer, the supplemental bill arrives months later addressed to the owner, and it is set aside as a duplicate or an error. It is neither. On a high-value Los Angeles purchase where the assessed value has just jumped by many millions, a supplemental bill can be a very large sum, and it is subject to the same delinquency consequences as any other property tax. Budget for it at closing rather than discovering it in month seven.
The Los Angeles County Treasurer and Tax Collector publishes the schedule for secured property taxes. The first installment is due November 1 and becomes delinquent after December 10. The second installment is due February 1 and becomes delinquent after April 10. If a delinquency date falls on a weekend, the deadline moves to the next business day. A ten per cent penalty applies to unpaid amounts after each delinquency date, and state law adds a ten dollar cost on the second installment. Those dates apply to the regular secured bill; supplemental bills carry their own due dates, printed on the bill itself.
Those dates are worth putting in a calendar rather than trusting to memory, because they are unintuitive. The fiscal year runs from July, bills are issued in the autumn, and the two installments straddle the new calendar year. Buyers arriving from other states routinely assume a single annual bill payable at a familiar time, and the penalty for that assumption is a fixed percentage rather than a nominal late fee. The Treasurer and Tax Collector, rather than the assessor, issues these bills and collects payment, so billing questions and valuation questions go to different offices. Sending a query to the wrong one costs weeks.
For budgeting, the useful discipline is to model three separate obligations in your first two years: the prorated share of the current annual bill handled through escrow, the supplemental bill or bills that follow reassessment, and then the first full annual bill computed on your new base year value. Ask your escrow officer and your lender explicitly which of these the impound account will and will not cover. The answer is often that it covers the annual bill only, which leaves the supplemental squarely with you. Confirm the answer in writing rather than by conversation.
Proposition 19 took effect on February 16, 2021 and substantially narrowed the parent-child exclusion. The Board of Equalization explains that transfers of a family home or family farm between parents and their children may qualify for exclusion from reassessment, but only where the transferee occupies the residence as a principal residence and files for either the homeowners' or disabled veterans' exemption within one year from the date of death or transfer. The claim itself, on form BOE-19-P, must be filed within three years from the date of death or transfer, or before a transfer to a third party, whichever is earlier.
There is also a value limit, which did not exist in the old regime. The exclusion is capped at the property's factored base year value plus an inflation-adjusted amount. The Board of Equalization states that for the period February 16, 2025 through February 15, 2027 that amount is one million forty-four thousand five hundred eighty-six dollars. Market value above the factored base year value plus that cap is added back to produce an adjusted taxable value, so a very valuable inherited home can be partially reassessed even when the exclusion applies.
The larger change is what fell outside the exclusion entirely. Proposition 19 eliminated the exclusion for real property other than the principal residence. Under the prior rules, parents could pass a substantial amount of base year value in rental properties or second homes to children without reassessment. That pathway is gone. For families holding income property or a second residence in Los Angeles, this single change altered the arithmetic of holding versus selling, and it is the reason estate planning conversations in the city have become far more active since 2021.
The other half of Proposition 19 expanded the ability to move an existing low assessment to a new home. The Board of Equalization states that the base year value transfer rules took effect April 1, 2021, and that homeowners aged fifty-five or older, along with severely and permanently disabled persons, may use the benefit three times, replacing the previous one-time limit. The replacement property must be purchased or newly constructed within two years of selling the original home, and if the replacement is purchased first, the original home must sell within two years. Claims must be filed within three years of the date the replacement dwelling is purchased.
The transfer is not limited to a less expensive home, which is the change most homeowners find useful. Where the replacement costs more, the Board of Equalization gives the formula: the new taxable value is the transferred base year value plus the difference between the replacement home's full cash value and the adjusted full cash value of the original home. Its published example takes an original home sold at four hundred thousand dollars with a factored base year value of one hundred thousand dollars, a replacement bought in the first year for six hundred thousand dollars, compares six hundred thousand against one hundred five per cent of four hundred thousand, and arrives at a taxable value of two hundred eighty thousand dollars.
For long-tenured Los Angeles owners, this provision is often the most consequential number in a move. A household that has owned in Hancock Park or the Palisades since the 1980s may be carrying an assessment that bears no relation to current value, and the difference between transferring it and starting fresh can exceed the moving costs by an order of magnitude. The rules on timing, filing windows and eligibility are unforgiving, so this is a conversation to have with your CPA and the county assessor before listing, not after. The county assessor's office can confirm eligibility before you commit to a move.
Not every change of title is a change in ownership for assessment purposes. The Board of Equalization describes a change in ownership as a transfer of a present interest, and it is deliberately broad: sale or purchase, gift or inheritance, voluntary or involuntary, by grant, devise, trust or contract of sale, including the addition or deletion of an owner. Once triggered, the assessor must reassess to fair market value as of the date ownership changed. But several common transfers are excluded. The breadth of that definition is the point: many transfers that feel administrative rather than economic still qualify as a change in ownership.
The Board identifies interspousal transfers as automatically excluded, including transfers in and out of a trust for a spouse's benefit, adding a spouse to a deed, and transfers on a spouse's death. Transfers of real property to a revocable trust are excluded where the transferor retains the power to revoke, or where the trust is created for the transferor's benefit. Legal entity restructuring is excluded when the proportional ownership interests of the transferors and transferees remain the same after the transfer. Each of these exclusions carries its own conditions and, in most cases, its own claim form, so none of them is automatic in the sense of requiring nothing from you.
That last exclusion is where sophisticated buyers most often go wrong. Proportionality is a strict test, and separate rules govern changes in control of a legal entity that holds California real property. Adding a partner, redeeming an interest, or reorganising ownership among family members can produce a reassessment that no one anticipated, sometimes years after the underlying purchase. If your acquisition involves an LLC, a partnership, a trust with multiple beneficiaries, or anything other than individuals taking title directly, treat the assessment question as a matter for counsel from the outset.
The most useful habit is to estimate your own bill rather than inheriting the seller's. Start from your purchase price as the likely new base year value, apply the one per cent ad valorem rate, then ask the county for the voter-approved debt rate and direct assessments applicable to that specific parcel, because these vary by location and are not uniform across the county. Add the homeowners' exemption if you will occupy the property as a principal residence and qualify. Treat the result as an estimate to be confirmed, not a quote.
Then plan for the mechanics. Confirm with your lender whether an impound account covers only the annual secured bill. Diarise November 1, December 10, February 1 and April 10. Expect supplemental billing to arrive months after closing, and keep the funds available rather than assuming escrow settled everything. If you make improvements, remember that completion of new construction is its own reassessment trigger for the added value, which means a significant renovation has a property tax consequence that should be modelled alongside the construction budget. Permits are visible to the assessor, so this is not a matter of discretion.
Finally, know which office answers which question. The Los Angeles County Assessor determines assessed value and processes exclusion claims and exemption filings. The Los Angeles County Treasurer and Tax Collector issues bills and collects payment. The California State Board of Equalization publishes the statewide rules and the forms behind Propositions 13 and 19. If a figure you have been given does not trace back to one of those three, it is not yet verified, and on a purchase of this size verification is cheap relative to the alternative. Ask which office produced any figure before you rely on it.
This guide summarises published rules from the California State Board of Equalization and Los Angeles County and is not legal or tax advice; assessment outcomes depend on facts specific to your title, timing and filings, so confirm your situation with the county assessor and your own CPA and attorney.
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