California property tax law caps the base rate at 1% of a property’s assessed value and limits annual assessment increases to 2% or the rate of inflation, whichever is lower. Those two rules, set by Proposition 13, keep your tax bill tied to what you paid for the property rather than what it would sell for today. Exemptions, special assessments like Mello-Roos, transfer rules under Proposition 19, and formal appeal rights all layer on top and can meaningfully change what you actually owe.
The 1% Cap and the 2% Annual Increase Limit
Article XIII A of the California Constitution sets the maximum ad valorem property tax rate at 1% of a property’s full cash value.1Justia. California Constitution Article XIII A – Tax Limitation Full cash value is the appraised value when you buy the property, when new construction finishes, or when ownership changes. Your county assessor uses that figure as the baseline for every future bill instead of re-appraising to current market value each year.
From there, Section 2 of Article XIII A allows the assessed value to rise annually by the rate of inflation or 2%, whichever is lower.2Justia. California Constitution Article XIII A – Tax Limitation – Section 2 Revenue and Taxation Code Section 51 reinforces that the annual increase can never exceed 2%, even when actual inflation runs higher.3California Legislative Information. California Revenue and Taxation Code RTC 51 A home bought in 1990 might carry an assessed value of $300,000 while the identical house next door, sold last year for $1.2 million, sits on a tax base four times higher. Long-term owners benefit; neighbors on the same street can pay very different bills.
What Triggers a Reassessment
Your assessed value stays locked in unless a specific event forces reassessment to current market value. The most common trigger is a change in ownership. Revenue and Taxation Code Section 60 defines this broadly as a transfer of a present interest in real property, including its beneficial use.4California Legislative Information. California Code Revenue and Taxation Code 60 – Change in Ownership and Purchase Standard home sales are the obvious case, but the definition also covers transfers between corporations and their shareholders, and the creation of leases of 35 years or longer when renewal options are counted.5California Legislative Information. California Revenue and Taxation Code 60 – Change in Ownership When a deed is recorded, the assessor reviews it and, if a qualifying event occurred, sets a new base year value equal to the fair market value on the date of transfer.
New construction is the other major trigger. Adding a bedroom, building a pool, or finishing a major renovation creates additional assessed value based on the improvement’s market worth at completion. Only the new portion gets a contemporary assessment; the original structure keeps its existing base year value. If you own a home assessed at $400,000 and add a $150,000 addition, your new total assessed value is $550,000, not the full market value of the improved property.
Supplemental Tax Bills After a Purchase
After a reassessment event, most new owners are caught off guard by supplemental tax bills. These are one-time bills covering the gap between the old assessed value and the new base year value, prorated for the remaining months in the fiscal year. They arrive separately from the regular annual tax bill and have their own due dates printed on the bill itself.
Revenue and Taxation Code Section 75.11 governs the calculation. If the change in ownership or new construction happens between January 1 and May 31, two supplemental assessments may be placed on the roll, one for the current year and one for the upcoming year. If the event falls between June 1 and December 31, a single supplemental assessment covers the current fiscal year.6California Legislative Information. California Revenue and Taxation Code RTC 75.11 Closing in March can produce two supplemental bills, while a September closing typically generates one. Budget for them in your first year of ownership.
Exemptions and Exclusions That Lower What You Pay
California offers several ways to reduce your property tax burden. Some lower the assessed value directly; others protect against reassessment when property moves within a family or when qualifying homeowners relocate.
Homeowners’ Exemption
If you occupy your home as a primary residence on January 1, you qualify for a $7,000 reduction in assessed value under Article XIII, Section 3 of the California Constitution.7Justia. California Constitution Article XIII Section 3 – Taxation At the 1% base rate, that works out to roughly $70 in annual savings.8California State Board of Equalization. Homeowners’ Exemption It is a small benefit, but you have to file for it. Contact your county assessor’s office after you buy to submit the one-time application.
Disabled Veterans’ Exemption
Veterans with a service-connected disability rated at 100%, or compensated at the 100% rate for unemployability, can exempt a much larger portion of their home’s value. For the 2026 assessment year, the basic exemption is $180,671. Veterans with household income at or below $81,131 qualify for the low-income exemption of $271,009.9California State Board of Equalization. Disabled Veterans’ Exemption Increases for 2026 These figures are adjusted annually for inflation. You cannot claim both this and the homeowners’ exemption; you choose the one that saves more.
Proposition 19 Base Year Value Transfers
Proposition 19, which took effect in April 2021, lets certain homeowners carry their low assessed value to a replacement home anywhere in California. You must be at least 55 years old, severely disabled, or a victim of a wildfire or other natural disaster. The replacement home must be purchased or newly constructed within two years of selling the original, and you must use it as your primary residence.10California State Board of Equalization. Proposition 19 Base Year Value Transfer Guidance Questions and Answers
If the replacement home costs the same as or less than the original’s market value at the time of sale, the old base year value transfers in full. If it costs more, the difference in market value gets added to the transferred base year value.11Board of Equalization. Proposition 19 – The Home Protection for Seniors, Severely Disabled, Families, and Victims of Wildfire or Natural Disasters Act Seniors and disabled homeowners can use the benefit up to three times. Wildfire and disaster victims have no limit on the number of transfers.10California State Board of Equalization. Proposition 19 Base Year Value Transfer Guidance Questions and Answers
Parent-to-Child and Grandparent-to-Grandchild Transfers
Proposition 19 also tightened the rules for passing property between generations. Before February 2021, parents could transfer a primary residence and up to $1 million in other property to their children without triggering reassessment. Now only the family home qualifies, the child must use it as their own primary residence, and there is a value cap.
The exclusion protects only the first $1,044,586 (for transfers between February 16, 2025, and February 15, 2027) of value above the property’s factored base year value. If the home’s current market value exceeds the existing assessed value plus that cap, the excess gets added to the new tax base.12California State Board of Equalization. Proposition 19 Fact Sheet The Board of Equalization adjusts this dollar figure every two years for inflation. If a child inherits a home worth $2 million with a base year value of $200,000, the assessed value becomes roughly $755,414 rather than resetting to the full $2 million. If the child does not move in and file for the homeowners’ exemption within one year of the transfer, the property is fully reassessed with no exclusion.
Mello-Roos and Special Assessments
The 1% cap applies only to the base ad valorem tax. Many California homeowners also pay special taxes authorized by the Mello-Roos Community Facilities Act of 1982.13Justia. California Government Code Chapter 2.5 – The Mello-Roos Community Facilities Act of 1982 Local agencies use the law to form Community Facilities Districts that issue bonds to finance schools, roads, parks, fire stations, and similar infrastructure.
Mello-Roos taxes work differently from regular property taxes. They are not based on property value. The district calculates each parcel’s share using factors like lot size, square footage, or land use type, and those charges appear as separate line items on your annual tax bill. The district must secure voter approval before levying the tax, and the lien stays attached to the property until the underlying bonds are fully repaid.14California Legislative Information. California Government Code 53321 – Proceedings to Create a Community Facilities District Newer developments tend to carry heavier Mello-Roos obligations because the surrounding infrastructure was bond-financed. Investigate these charges before closing on any home in a planned community. They can add thousands per year and are not subject to Proposition 13’s 1% limit.
Payment Deadlines and Late Penalties
California’s property tax fiscal year runs July 1 through June 30, and the annual bill is split into two installments. The first installment is due November 1 and becomes delinquent after 5 p.m. (or the close of business, whichever is later) on December 10.15California Legislative Information. California Revenue and Taxation Code 2617 The second installment is due February 1 and goes delinquent after April 10. If a deadline falls on a weekend or holiday, it extends to the next business day.
A late first installment incurs a flat 10% penalty.15California Legislative Information. California Revenue and Taxation Code 2617 A late second installment also triggers a 10% penalty plus an additional cost. Mailed payments count as timely if the envelope carries a U.S. Postal Service postmark dated on or before the delinquency date. If the postmark is missing or illegible and the payment arrives late, you owe the penalty regardless of when you dropped it in the mailbox. Online and in-person payments must be completed by close of business on the deadline.
What Happens When Taxes Go Unpaid
If both installments remain unpaid at the end of the fiscal year, the property is declared tax-defaulted at 12:01 a.m. on July 1.16State Controller’s Office. Public Auctions and Bidder Information Once in default, the unpaid balance accrues interest at 1.5% per month, and a $15 redemption fee is added. Over a full year, that monthly rate adds up to an 18% effective penalty.
You have a redemption period to pay off the delinquent taxes, penalties, and interest before the county can sell the property. For residential property, that period is five years. For nonresidential commercial property, it is three years.17State Controller’s Office – California. County Tax Collectors’ Reference Manual – Chapter 6000 After the redemption period ends, the tax collector must attempt to sell the property at public auction within four years.16State Controller’s Office. Public Auctions and Bidder Information Missing a single year will not cost you your home immediately, but the hole deepens fast. Contact the tax collector’s office early about an installment plan rather than letting 18% annual interest run on the full balance.
Postponement for Seniors and Disabled Homeowners
The State Controller’s Office runs a Property Tax Postponement program that lets qualifying homeowners defer their current-year property taxes. The state pays the bill and places a lien on the home, which must be repaid when the property is sold or the homeowner dies. You must be a senior, blind, or have a disability; your annual household income cannot exceed $55,181; and you must have at least 40% equity in the home.18State Controller’s Office – California. Property Tax Postponement The filing deadline for the 2025–26 fiscal year is February 10, 2026. The program is separate from the Proposition 19 base year value transfer and can be used alongside it.
How to Challenge Your Assessed Value
If you think your property is overvalued, California gives you two paths: a Proposition 8 decline-in-value review and a formal assessment appeal.
Proposition 8 Decline-in-Value Review
When the current market value of your property drops below its assessed value as of the January 1 lien date, you may be entitled to a temporary reduction under Proposition 8.19California Department of Tax and Fee Administration. Decline in Value – Proposition 8 The decline can come from a slumping real estate market, neighborhood changes, or physical damage to the property. Many county assessors proactively review values during downturns, but do not assume yours was included. File a decline-in-value application with your county assessor to be sure. The reduction is temporary. If market values recover, the assessor can raise your assessed value back up to the original factored base year value (your purchase price adjusted by up to 2% per year).
Formal Assessment Appeals
For broader valuation disputes, file an Application for Changed Assessment with the Clerk of the Assessment Appeals Board (typically housed within the Board of Supervisors). The annual filing window opens July 2 and closes on either September 15 or November 30, depending on whether your county assessor mails assessment notices to all secured-roll taxpayers by August 1.20California State Board of Equalization. County Assessment Appeals Filing Period Miss that window and you wait a full year.
The application asks for your Assessor’s Parcel Number (printed on your tax bill), the current assessed value, and your opinion of fair market value. The strongest appeals come with comparable sales data: recent sales of similar homes in your neighborhood that closed near the January 1 lien date. Three to five solid comparables showing lower per-square-foot values than your assessment carry more weight than a single data point. Photographs documenting deferred maintenance, structural problems, or adverse neighborhood conditions also help. The burden of proof falls on you, so bring concrete evidence.