Contact: Mark Church, Assessor-County Clerk-Recorder & Chief Elections Officer
Alternate: Jim Irizarry, Assistant Assessor-County Clerk-Recorder

(Redwood City, CA) San Mateo County Assessor Mark Church announced today that the County’s Property Assessment Roll climbed to a new record of more than $357.6 billion in assessed value for the 2026-27 fiscal year, representing growth of $16.6 billion, or 4.85%, over the prior year.

“San Mateo County continues to demonstrate remarkable economic resilience and long-term stability,” said Church. “Despite higher interest rates, housing affordability challenges, and shifting commercial real estate conditions, the County continues to benefit from a diverse economy, world-class employers, and sustained demand for property. This year’s assessment roll growth reflects continued confidence in San Mateo County’s future.”

This growth was driven by several factors working together, including inflation-adjusted Proposition 13 values, property transfers, new construction, and completed development projects across multiple property types. Residential properties remained the primary source of growth, while commercial markets showed signs of stabilization after several years of post-pandemic adjustment.

2025 Market Review and Summary
This year’s growth was especially notable because 2025 was marked by economic crosscurrents. Elevated interest rates, inflationary pressures, affordability challenges, layoffs in portions of the technology and life science sectors, and broader economic uncertainty affected housing demand, development financing, and commercial real estate investment. The Federal Reserve noted in December 2025 that inflation and uncertainty about the economic outlook remained elevated.

Even in that environment, San Mateo County continued to show remarkable stability. High household incomes, a concentration of technology and life science employers, limited housing supply, continued residential demand, and long-term investor confidence helped sustain assessment roll growth while many other markets faced greater volatility.

Mortgage rates remained a significant constraint. Freddie Mac’s Primary Mortgage Market Survey continued to show 30-year fixed mortgage rates remained elevated, generally in the 6% range, and were in the mid-6% range by mid-2026, limiting affordability and discouraging some owners with lower existing mortgage rates from selling. These conditions were especially difficult for first-time and mid-market buyers, but the County’s higher-income buyer pool and constrained housing supply helped support property values.

San Mateo County also benefited from an economic profile few counties can match. Census-based estimates show the County’s population continued to recover from pandemic-era declines, reaching approximately 743,568 residents in 2025. The County’s labor market also remained among the strongest in California, with unemployment improving from 3.6% in December 2025 to 3.1% in May 2026, the lowest rate in the state, according to Employment Development Department (EDD) data.

At the same time, the County also benefited from another Bay Area cycle of wealth creation tied to artificial intelligence, advanced technology, and related equity markets. Redfin reported that luxury ZIP codes in the San Francisco Bay Area saw a 13.4% average increase in home prices in the two years following the launch of ChatGPT, substantially outpacing other market segments. That trend is consistent with continued demand in San Mateo County’s most affluent residential communities, where limited inventory and competition among high-income buyers continue to support values. Together, these factors helped San Mateo County’s residential real estate market remain resilient in 2025.

Commercial real estate varied by sector. Office and life science markets continued to adjust to higher capital costs, post-pandemic space needs, and tenant right-sizing. Although the pace of major development activity has moderated, substantial projects remain underway across residential, mixed-use, life science, and other sectors, reflecting continued confidence in San Mateo County’s long-term economic future.

“San Mateo County is not immune to economic uncertainty,” said Church. “But this year’s Assessment Roll shows that the County continues to stand on a remarkably strong foundation. Stability itself is a strength, and this year’s continued roll growth reflects confidence in San Mateo County’s long-term future, its workforce, its communities, and its role as not only one of the Bay Area’s but also California’s most important economic engines.”

Highlights of the 2026-27 Roll
The 2026-27 Combined Assessment Roll represents the sixteenth consecutive year of record-setting growth, a notable result in a year when higher interest rates, affordability pressures, and commercial real estate adjustments continued to test local markets.

“San Mateo County continues to serve as an anchor of stability in a volatile economy,” Church added. “The County’s diversified employment base, strong household incomes, innovation sectors, and highly desirable residential communities continue to support long-term demand for property. This year’s roll growth confirms that San Mateo County remains one of the most desirable places in the nation to live, work, build, and invest.”

All twenty cities and unincorporated areas in the County experienced increases in assessed value, ranging from 2.26% to 7.34%, with an overall rise of 4.85%. Unincorporated areas, including San Francisco International Airport (SFO), experienced a growth rate of 4.87%.

Of the $16.83 billion increase in the Secured Roll, approximately $10.3 billion, or 61%, resulted from new construction, changes in ownership, and an increase in the secured Business Personal Property (BPP) values. Approximately $6.6 billion, or 39%, came from the California Consumer Price Index (CCPI) adjustment and other secured roll changes.

Approximately 1% of the assessed roll supports the County’s property tax base, equating to $3.58 billion in revenue. Of this amount, 51% will go to schools ($1.82 billion, an increase of $80 million from last year), 25% to the County ($894.08 million, an increase of $41.4 million from last year), 16% to cities, 7% to special districts, and 1% to former redevelopment agencies.

Top 5 Cities by Percentage Growth in Assessed Value: Brisbane 7.34%; Menlo Park 6.96%; Woodside 6.91%; Millbrae 6.82%; Atherton 6.71%.

Top 5 Cities by Dollar Growth in Assessed Value: Menlo Park $2.07 billion; San Mateo $1.55 billion; Redwood City $1.24 billion; Atherton $1.17 billion; Burlingame $1.15 billion. The cumulative assessed value increases reflected in these five cities contributed to about 43.4% of the total 2026-27 Roll increase.

Value Declines: The Assessor’s Office reviewed over 7,400 properties for potential declines in value for 2025. Of those, 6,572 properties qualified for a reduction due to their market value being lower than their assessed value. This resulted in about $3.5 billion in temporary value reductions compared with the 2025-26 Prop 13 values.

Supporting Public Services
The Assessment Roll is the foundation for local property tax revenues that fund public schools, the county, cities, special districts, public safety, transportation, parks, libraries, and other essential services throughout San Mateo County.

“Every increase in assessed value translates into resources that directly benefit residents,” Church said. “Property taxes support the schools our children attend, the public safety services our communities rely upon, and the infrastructure that sustains our quality of life.”

SECURED ROLL
The Secured Roll represents 96.3% of the Combined Roll and includes 223,003 commercial, residential, and agricultural parcels. For FY 2026-27, the Secured Roll increased to $344.5 billion, a growth of $16.83 billion or 5.14% over the FY 2025-26 roll, reflecting continued economic growth in San Mateo County.

New Major Development
Major commercial, residential, mixed-use, and master planned development projects continued to be significant contributors to the County’s assessment roll growth in 2025. Projects tracked by the Assessor’s Office include developments of 80,000 square feet or more that are under review, entitled, under construction, or completed.

In 2025, approximately 4 million square feet of major development projects were completed countywide, representing a substantial increase from the approximately 3.3 million square feet completed in 2024. The completed projects consisted primarily of life science, residential, mixed-use, office, and other developments distributed throughout the County.

The County’s major development inventory being tracked now totals approximately 105.6 million square feet, an increase from approximately 99.5 million square feet reported a year ago. Of this total, approximately 14.4 million square feet are currently under construction, 17.8 million square feet have received planning approvals, and 34.5 million square feet remain under review.

Since 2015, approximately 36.3 million square feet of major construction projects have been completed throughout San Mateo County, reflecting sustained long-term investment in housing, life science facilities, office development, hospitality, and mixed-use projects.

Commercial and industrial projects account for the largest share of the County’s major development inventory at approximately 55.9%, followed by residential projects at 21.6%, mixed-use projects at 15.8%, and master planned community projects at 6.6%. Life science projects remain the largest individual development category, accounting for approximately 31.4% of all major development activity tracked by the Assessor’s Office.

Top 5 Cities for Major Development
The following cities contain the largest concentration of major development projects of at least 80,000 square feet that are under review, entitled, under construction or completed: Redwood City, 21.15 million square feet; South San Francisco, 19.43 million square feet; Menlo Park, 13.68 million square feet; Brisbane, 8.27 million square feet; and Burlingame, 7.22 million square feet. Notably, Redwood City now contains the County’s largest concentration of major development activity, surpassing South San Francisco.

“The continued strength of San Mateo County’s development pipeline reflects long-term confidence in the County’s economy. While the office sector continues to adjust to changing workplace trends, substantial investment remains focused on life sciences, housing, mixed-use development, and transit-oriented projects that support future economic growth,” noted Church.

Completed Commercial Projects in 2025
Commercial development activity remained strong in 2025, led primarily by life science and office projects. Major life science completions included 200 Twin Dolphin Drive in Redwood City, 1091 Industrial Road, 1030 Brittan Avenue, and 405 Industrial Road in San Carlos, as well as 201 and 231 Adrian Road in Millbrae. Additional commercial completions included South Main Mixed-Use, now known as Elco Yards, in Redwood City, Bay Meadows Station 1 at 2750 South Delaware Street in San Mateo, Peninsula Innovation Point at 555-577 Airport Boulevard in Burlingame, and the Primary School campus expansion at 1200 Weeks Street in East Palo Alto. In total, approximately 1.9 million square feet of commercial and institutional development space was completed during 2025.

Completed Residential Projects in 2025
Residential development activity accelerated significantly in 2025 and accounted for more than half of all major completed square footage during the year. Notable completions included Revery Apartments and Hanover in Burlingame; the Waters Office Park redevelopment in San Mateo; the residential development at 1095 Rollins Road in San Bruno; and Middle Plaza in Menlo Park. In total, approximately 2.7 million square feet of residential and mixed-use development was completed during 2025.

Median Prices and Sales Activity
According to annual data reported by the San Mateo County Association of REALTORS® (SAMCAR), the median sales price of a single-family home increased to $1,980,000, up approximately 1.5% from $1,950,000 in 2024. Sales activity also improved, with 3,822 single-family homes sold, an increase of approximately 7.1% over the prior year. Total single-family sales volume exceeded $10.1 billion, up approximately $1.0 billion, or 11.4%.

The condominium market was more mixed. The median condominium sales price declined slightly by 0.7%, from $915,000 in 2024 to $909,000 in 2025. Condominium sales declined by approximately 3.9%, from 1,164 units to 1,119 units, while total sales volume decreased from approximately $1.23 billion to $1.14 billion.

Early 2026 market activity showed renewed momentum. SAMCAR reported that the median sales price for single-family homes increased from $1,927,000 in January to $2,200,000 in May, while average sale price rose from $2.74 million to $3.01 million. Single-family home sales increased from 157 homes in January to 375 homes in May, and May sales volume exceeded $1.1 billion. From March through May, single-family homes countywide sold at approximately 107% to 109% of list price received, indicating continued buyer competition for well-positioned homes.

The condominium market also improved in early 2026, with the countywide median price rising from $830,000 in January to $1,130,000 in May and average days on market improving from 60 days to 34 days. Although monthly condominium figures are more sensitive to product mix, the early 2026 data suggest a strengthening spring market after a softer 2025.

Despite this renewed momentum, transaction volume remained below 2021 peaks. Single-family home sales remained below the 2021 peak of 5,452 units, and condominium sales remained below the 2021 peak of 1,935 units, showing that demand remains strong but continues to be constrained by limited inventory, elevated financing costs, and affordability pressures.

Proposition 19: Impact on Assessed Values
Approved by California voters in November 2020, Proposition 19 imposed tighter restrictions on intergenerational transfer exclusions and expanded the ability for homeowners over age 55 to transfer base year value to a replacement principal residence. The 2026–27 Assessment Roll reflects these changes, with 212 base year transfers, of which 45% originated from outside San Mateo County.

Reduction in Assessed Value - Proposition 8 / Decline in Value Program
Under California Proposition 8/Decline in Value Program, property tax relief is available when a property's market value drops below its assessed value. The Assessor’s Office reviewed over 7,400 properties for potential declines in 2025, as compared to 7,600 in 2024.

Of those, 6,572 properties qualified for a reduction, with 2,484 partially restored, totaling $3.5 billion in relief. Despite this, the number remains well below the historical high of 34,700 properties in decline in 2010.

An additional 624 properties were fully restored, contributing $236 million in value returned to the roll. Among the 264 commercial properties receiving relief, 4 more qualified in 2025 than in 2024. However, this remains well below the high of 604 commercial declines in 2011. In total, commercial properties accounted for $998 million of the $3.5 billion in relief.

Over 6,500 affected property owners will receive their FY 2026–27 Assessed Value Notices, including those now restored to their factored base year (Prop 13) value.

Annual Inflation Factor
Under California Proposition 13, property assessments are adjusted annually based on the California Consumer Price Index (CCPI), limiting the increase to no more than two percent. The full two percent inflation factor was applied to all real property that did not undergo a change in ownership or new construction.

Recorded Foreclosures
In 2025, 40 Trustee’s Deeds were recorded, down from 47 in 2024. Notices of Default also declined to 314, compared to 347 the previous year. Despite elevated mortgage interest rates and ongoing affordability challenges, foreclosure activity remained historically low and well below the peak of 5,058 Notices of Default recorded during the foreclosure crisis in 2009.

“The continued decline in foreclosure activity reflects the strength of San Mateo County’s economic fundamentals,” stated Church. “As one of the nation’s highest-income counties, supported by leading technology and life sciences industries, the County has remained well-positioned to withstand higher interest rates and economic uncertainty while maintaining historically low levels of mortgage distress.”

UNSECURED ROLL
The Unsecured Roll totaled $13.18 billion, a decrease of $275.4 million, or 2.05%. The Unsecured Roll represents 3.7% of the Property Assessment Roll and includes business and personal property, possessory interests, and air transportation-related assets at San Francisco International Airport (SFO).

Addenda:

2026-27 Local Combined Roll
2026-27 Local Secured Roll 
2026-27 Local Unsecured Roll
2026-27 Residential Decline in Value Summary