Property Tax California: Prop 13, County Rates, and Exemptions for 2027

The median California homeowner pays $5,124 a year on a home worth $734,700, according to the Census Bureau, an effective property tax rate of 0.70 percent. By county, that rate runs from 0.58 percent in Trinity County to 0.88 percent in Kern County. This California property tax calculator covers all 58 counties: it multiplies your value by the rate owners in your county actually pay (median tax divided by median home value), then shows the local median bill and the county’s average levy for recent buyers. Enter current market value, not the assessed value printed on your bill.

Proposition 13: The Price You Paid Sets the Tax

California taxes a home on what it was worth when you bought it, not what it is worth today. Proposition 13, approved on June 6, 1978, lets the assessor reappraise a property to market value only when it changes ownership or new construction is completed. That figure becomes the base year value, and from then on it may rise no more than 2 percent a year, tied to the California Consumer Price Index.

The same measure capped the general levy at 1 percent of assessed value. Local agencies can add rates only to repay voter approved debt, such as bonds approved by two thirds of voters or school facility bonds approved by 55 percent. The county auditor splits the 1 percent among the county, cities, schools, and special districts. For fiscal 2024-25 the Board of Equalization (BOE) reports $100 billion in levies statewide, with $53.5 billion going to schools and $46.5 billion to other local government.

For the 2026 roll, the index rose 3.307 percent (August 2024 to August 2025, since the federal shutdown left no October reading), yet assessors applied a factor of 1.02.

Why the Census Rate Sits Well Under 1 Percent

If the base levy is 1 percent, how does the typical owner pay 0.70 percent? The Census rate divides the median bill by the median market value owners report, and millions of homes are still assessed at base year values set decades ago and raised no more than 2 percent a year since. Averaged across a county, those old bases pull the effective rate well below the levy.

A recent buyer gets no such discount. The purchase price becomes the assessed value, taxed at the full levy for the tax rate area. BOE’s 2024-25 Annual Report lists the average countywide rate on assessed value: exactly 1.000 percent in Modoc and Sierra, 1.181 percent in Los Angeles, 1.220 percent in Alameda, and 1.248 percent in Kern, the highest. The calculator shows your county’s figure. Many California bills also carry charges not based on value, such as parcel taxes, Mello-Roos special taxes in newer subdivisions, and benefit assessments.

County Rates, Trinity to Kern

On the ACS 2024 five year estimates, Kern has the highest effective rate at 0.88 percent, followed by Placer at 0.84, Contra Costa at 0.83, and San Benito at 0.81. Trinity is lowest at 0.58 percent, then Del Norte, Mariposa, and San Mateo at 0.61. The middle county sits at 0.70 percent, matching the state. Marin (0.78) and Santa Clara (0.68) are estimates, modeled from Census county totals because their median bill is published only as “$10,000 or more”; they are left out of the rankings above.

San Mateo’s rate is among the lowest, yet its median home value of $1,559,600 produces a median bill of $9,519. San Francisco has the largest published median bill, $9,862 on a median value of $1,394,500. Kern’s median bill is just $2,984 because its median home is worth $338,300.

Two worked examples from the calculator’s data:

• Los Angeles County, $900,000 home: $900,000 times 0.68 percent is $6,120 a year, or $510 a month, $445 above the county’s $5,675 median bill. Had you just bought it for $900,000, the 1.181 percent average levy points to about $10,629, or roughly $10,546 after the homeowners’ exemption.
• Riverside County, $600,000 home: $600,000 times 0.78 percent is $4,680 a year, or $390 a month, $332 above Riverside’s $4,348 median.

The same $400,000 house comes to $3,520 a year at Kern’s effective rate and $2,320 at Trinity’s.

Supplemental Bills After You Buy

A purchase resets the assessed value immediately, so the county issues a supplemental assessment for the difference between the new and old values, prorated over the months left in the fiscal year (July 1 to June 30). A sale or completed construction between January 1 and May 31 brings two supplemental bills: one for the rest of the current year and one for all of the next. The Los Angeles County Treasurer and Tax Collector mails these bills to the owner, not the lender, and impound accounts generally do not cover them, so budget for one after closing.

Decline in Value Reviews and Formal Appeals

Proposition 8, the November 1978 amendment, sets the floor. Each January 1, your assessed value must be the lower of your factored base year value or current market value. A market dip below the factored base means a temporary lower value, and in recovery that value can rise more than 2 percent a year until it reaches the factored base again.

Start with the assessor: ask how your value was set and, if local prices have dropped, request an informal decline in value review. If that fails, file an Assessment Appeal Application with the clerk of the board of supervisors, acting as the county board of equalization or through an assessment appeals board. The regular window opens July 2 and closes September 15 in counties where the assessor mails value notices to every owner, or November 30 where it does not; BOE posts each county’s date. Supplemental and escape assessments must be appealed within 60 days of the notice’s mailing.

Exemptions, Veterans’ Relief, and Base Year Transfers

Homeowners’ exemption. The constitution takes $7,000 off the assessed value of an owner occupied principal residence, about $70 a year at the 1 percent levy. File once with the assessor by February 15 for the full amount, or by December 10 for 80 percent. Rentals and second homes are ineligible.

Disabled veterans’ exemption. Veterans rated 100 percent disabled, or paid at the 100 percent rate for unemployability, and qualifying unmarried surviving spouses can exempt a large slice of home value. For the 2026 lien date, the basic exemption is $180,671, and the low income exemption is $271,009 within an $81,131 household income limit. On May 22, 2026, BOE set the indexed 2027 figures: $185,889 basic, $278,836 low income, and an $83,474 income limit.

Proposition 19. Since April 1, 2021, owners who are 55 or older, severely disabled, or who lost a home to wildfire or natural disaster can move their taxable value to a replacement home anywhere in California, up to three times, if they buy within two years of selling. A pricier replacement adds the difference to the transferred value. Prop 19 also narrowed the parent to child exclusion from February 16, 2021: the home must become the child’s principal residence, and only the factored base plus an adjusted $1 million ($1,044,586 since February 16, 2025) escapes reassessment.

Postponement. The State Controller’s program lets seniors, blind owners, and owners with a disability defer current year taxes with at least 40 percent equity and household income of $57,002 or less. The 2026-27 filing period runs October 1, 2026 through February 10, 2027, and the deferred amount is secured by a lien.

November and February Installments, and Tax Default

The county tax collector mails the secured bill by November 1, payable in two equal halves. The first is due November 1 and turns delinquent after December 10; the second is due February 1 and turns delinquent after April 10. A late installment draws a 10 percent penalty. If taxes remain unpaid past the date in the notice of impending default, the property is declared tax defaulted and redemption penalties of 1.5 percent a month accrue. After five years without redemption, the county can sell it at public auction.

What 2027 Brings

The January 1, 2027 lien date sets values for the 2027-28 bills mailed that fall, with the inflation step again capped at 2 percent. The new construction exclusion for active solar systems, as written in September 2026, covers only systems that qualify before January 1, 2027 (Revenue and Taxation Code section 73, as amended by SB 710 in 2025); ask the assessor before a later install. County rates here come from the ACS 2024 five year release, which pools surveys from 2020 through 2024; we refresh them each December, along with veterans’ amounts and BOE levy averages.

Sources: Census Bureau tables B25103 and B25077 from the 2024 five-year American Community Survey; California State Board of Equalization Publication 29 (March 2025), 2024-25 Annual Report, and Letters to Assessors 2026/002 and 2026/019; BOE Proposition 19 guidance; State Controller’s Office Property Tax Postponement Program; Los Angeles County Treasurer and Tax Collector. Verify your assessed value with your county assessor and your bill with your county tax collector.