Santa Clara County’s taxable property base reached a record $760.1 billion for fiscal year 2026-27, up 4.74% from last year, according to new figures released by the Assessor’s Office on July 6. The growth, however, is not evenly distributed across the county.
Los Altos posted one of the county’s largest increases in assessed property values, while Palo Alto also surpassed the county average. Mountain View, however, recorded one of the lowest growth rates as the city’s larger commercial tax base continued to feel the effects of a sluggish office market.
The figures come from the county’s annual assessment roll, the official record of the taxable value of all real estate, business property and personal property in Santa Clara County. The assessment roll determines the property tax base that helps fund local schools, cities, special districts and county services. The total net assessed value includes all real, business and personal property as of Jan. 1.
Los Altos, Palo Alto outpace Mountain ViewÂ
The new county figures show Los Altos’ assessment roll grew 6.43%, second only to Sunnyvale’s 7.17% increase. Palo Alto followed with 5.47% growth, above the countywide average of 4.74%, while Mountain View’s assessed value rose only 2.93%, ranking near the bottom among the county’s 15 cities.
Countywide, the 2026-27 assessment roll saw an increase of about $34.4 billion over last year. According to County Assessor Neysa Fligor, the increase was driven primarily by residential property sales, the maximum 2% Proposition 13 inflation adjustment and a rebound in new construction.
Sales, appreciation boost residential assessmentsÂ
 The differing growth rates reflect the makeup of each city’s tax base.
Communities dominated by single-family homes, including Los Altos and Palo Alto, continued to see rising assessment values from residential sales and appreciation. Countywide, roughly 17,000 homes changed hands in 2025, with residential transactions accounting for 82% of the value generated through ownership changes.
Ownership changes accounted for nearly half of this year’s increase in assessed value, adding $16.9 billion to the tax roll, the data shows. The annual Proposition 13 inflation adjustment added another $14 billion, while new construction contributed $4.9 billion, a 29% increase over the previous year. Business and personal property values climbed 7% to $54 billion, driven in part by higher equipment and construction costs.
“This year’s roll reflects the continued strength of our residential market, even as commercial real estate faces ongoing challenges,” Fligor said in a July 6 press release.
While residential properties accounted for most of this year’s growth, commercial properties faced declines. Office vacancies, less leasing activity and lower building values led to assessment reductions for many commercial properties across the county.
Office vacancies reduce assessments
Mountain View, which has a significant office and commercial property base, saw slower growth as some office properties continued to face high vacancy rates, a drop in leasing activity and declining values.
The county’s office vacancy rate has remained near 20% for the past two years, according to the Assessor’s Office, leading to a growing number of commercial properties receiving temporary assessment reductions under Proposition 8, which requires assessors to lower taxable values when market values fall below assessed values.
The number of properties receiving temporary Proposition 8 assessment reductions nearly tripled this year to 24,727, and commercial properties accounted for more than $5.6 billion in reductions to the county’s taxable property base.
According to the Assessor’s Office, 98% of the $153.6 billion of assessed value currently under appeal is commercial property. The Assessor’s Office expects another increase in commercial assessment appeals this year, Fligor stated.
The Assessor’s Office mailed Notification of Assessed Value cards to more than 500,000 property owners on June 30. Homeowners who believe their property’s assessed value exceeds its market value may request a free informal review through Aug. 8. Formal assessment appeals must be filed by Sept. 15.
More than half of Santa Clara County’s property tax revenue supports public schools and community colleges, with the remainder distributed among cities, special districts and county government.
San Mateo County
In neighboring San Mateo County, the annual assessment roll also reached a record high, climbing to $357.6 billion, an increase of 4.85% from the previous year. The growth rate was roughly in line with last year’s increase
Among Midpeninsula communities, Menlo Park posted one of the county’s strongest gains, with assessed values rising 6.96%, the second-highest growth rate among the county’s cities. Woodside and Atherton also saw growth above or near the county average, at 6.71% and 6.91%, respectively. Redwood City recorded one of the slower growth rates, at 3.59%, according to figures released on July 6 by San Mateo County Assessor-County Clerk-Recorder Mark Church’s office.
