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 increased by $15.6 billion, or 4.80%, from the previous year, reaching a record high of over $341.1 billion in assessed value.
"San Mateo County experienced another year of assessment roll growth in 2024, a clear indicator of the county’s economic strength despite high interest rates and economic uncertainty," said Church. “This year’s growth is a testament to our county’s continuing economic vitality.”
Driving this continued growth was sustained demand for residential real estate and ongoing commercial development, particularly in the life sciences and multi-family housing sectors. In total, 3.3 million square feet of major new construction was completed in 2024. “San Mateo County’s steady growth reflects its ability to thrive even with market volatility and reinforces its importance to the regional economy,” noted Church.
While growth remained positive, macroeconomic conditions, including elevated interest rates, inflationary pressures and economic uncertainty, slowed the rate of growth of the assessment roll. This year’s growth rate of 4.80% is slightly below last year’s 5.75%, continuing a downward trend from 2022, when the rate peaked at 8.3%.
Mortgage rates for 30-year fixed jumbo loans hovered above 7% throughout 2024, impacting affordability and inventory, especially for first-time and mid-level single-family homebuyers, according to Freddie Mac’s Primary Mortgage Market Survey. The condominium market also felt the effects, with the median price falling 1.4% to $915,000, according to the San Mateo County Association of REALTORS® (SAMCAR). Sales volume improved but remained below historical norms.
Despite high mortgage rates, the median sale price of single-family homes in the County increased by 8% to $1,950,000 in 2024, up from $1,805,000 in 2023. While inventory shortages pushed prices higher, affordability priced many buyers out of the market, which continued to limit transaction volume. “These annual figures demonstrate the local market dynamics and its ability to adjust to varying factors driving the growth this year,” Church stated.
San Mateo County residential home sales volume rose in 2024 but remained below historical highs. SAMCAR reported that 3,569 single-family homes sold in 2024, up 8% from 3,292 in 2023, but 35% lower than the high of 5,452 in 2021. Condominium sales increased 16.5% to 1,164 units in 2024, from 999 units in 2023, yet remained 40% below the 2021 high of 1,935 units.
Commercial real estate was another key driver of growth. According to Kidder Mathews’ Q4 2024 Life Sciences Market Report, over 4 million square feet of life sciences space was completed or under construction during 2024, with notable activity in South San Francisco, Millbrae, Burlingame and San Carlos. “San Mateo County’s leadership in life sciences continues to attract global capital and talent, driving our Assessment Roll and economic future,” said Church.
The residential multi-family sector also increased the assessment roll value. However, the office sector continued to face elevated vacancy levels, rising to 21.4% by year-end, per Cushman & Wakefield’s Q4 2024 MarketBeat Report.
The local labor market remained relatively stable despite layoffs in the tech and biotech industries. San Mateo County recorded the lowest unemployment rate in California at 3.3% in December 2024, according to the Employment Development Department (EDD), unchanged from the prior year. Although more than 1,200 life sciences jobs at large employers, such as Genentech, were lost in 2024 per Worker Adjustment and Retraining Notification (WARN) Act filings, gains in healthcare, hospitality, and public services helped offset broader employment losses.
San Mateo County continues to rank among the most prosperous counties in the nation.
According to U.S. News & World Report’s 2023 County Rankings, San Mateo County was the fourth wealthiest county in the U.S. and the second wealthiest in California, with a 2023 median household income of $156,000, according to the U.S. Census Bureau.
The County’s Q4 2024 housing affordability index remained at 17%, surpassing the state average of 15%, according to SAMCAR. Despite ongoing challenges, including high interest rates and job displacement, the County's diverse economy and commitment to innovation support a strong foundation for continued long-term growth.
Highlights of the 2025-26 Roll
“The 2025-26 Combined Assessment Roll represents the fifteenth consecutive year of record-breaking growth,” Church reported. “This is an extraordinary achievement that speaks to the county’s strong economic fundamentals making it a desired place to live, work and invest.”
All twenty cities and unincorporated areas in the County experienced increases in assessed value, ranging from 2.08% to 7.19%, with an overall rise of 4.80%. Unincorporated areas, including San Francisco International Airport (SFO), experienced a growth rate of 5.15%. Of the $15.6 billion increase in the Secured Roll, $9 billion, or 58%, resulted from new construction and changes in ownership. Approximately $6 billion, or 40%, came from the California Consumer Price Index (CCPI) adjustment and the remaining 2% from the Unsecured Roll and miscellaneous changes.
The Assessor’s Office reviewed over 7,500 properties in 2024 for possible declines in value, compared to 11,000 in 2023. A total of 6,580 properties qualified for Proposition 8 relief, including 2,941 with partial value restorations, resulting in $3.2 billion in assessed value reductions.
Top 5 Cities by Percentage Growth in Assessed Value:
- Millbrae: 7.19%
- Burlingame: 6.90%
- Brisbane: 6.82%
- Atherton: 6.49%
- Woodside: 6.40%
Top 5 Cities by Dollar Growth in Assessed Value:
- South San Francisco: $1.67 billion
- Redwood City: $1.52 billion
- San Mateo: $1.33 billion
- Burlingame: $1.22 billion
- Menlo Park: $1.15 billion
The cumulative assessed value increases reflected in these five cities contributed to over 44.2% of the total 2025-26 Roll increase.
Approximately 1% of the assessed roll supports the County’s property tax base, equating to $3.41 billion in revenue. Of this amount, 51% will go to schools ($1.74 billion, an increase of $80 million from last year), 25% to the County ($852.7 million, an increase of $39 million from last year), 16% to cities, 7% to special districts, and 1% to former redevelopment agencies.
SECURED ROLL
The Secured Roll represents 96.1% of the Combined Roll and includes 222,621 commercial, residential, and agricultural real properties. For FY 2025–26, the Secured Roll increased to $327.6 billion, a growth of $15.6 billion or 4.99% over the FY 2024–25 roll, reflecting continued economic growth in San Mateo County. The growth of the San Mateo County Secured Roll is primarily due to the following factors:
New Major Development
Although the pace of large-scale commercial, residential, and mixed-use construction projects slowed compared to the prior year, they remained significant contributors to this year’s roll growth. In 2024, more than 3.3 million square feet of new major developments, defined as projects of 80,000 square feet or more, were completed, compared to 3.8 million square feet in 2023.
Overall, over 15 million square feet of major new construction is projected to be completed within the next five years, including an estimated 4.6 million square feet in 2025. Currently, 15.1 million square feet are under construction, 19 million have received planning approval, and 33.1 million are under review. Since 2015, approximately 32.2 million square feet of major construction has been completed.
Commercial projects account for 56% of all major developments, followed by 21% residential and 16% mixed-use projects. The following table shows the percentages attributed to each major use type in the county’s development pipeline.
|
Property Category |
Development Size (Sq. Ft.) |
Percentage |
|---|---|---|
|
Life Science |
30,261,279 |
30.43% |
|
Office |
18,572,965 |
18.67% |
|
Hotel |
2,432,702 |
2.45% |
|
Senior Care Facility |
1,289,379 |
1.30% |
|
Industrial Park |
1,319,000 |
1.33% |
|
Retail |
1,189,218 |
1.20% |
|
Hospital |
758,800 |
0.76% |
|
School |
202,000 |
0.20% |
|
Community Center |
82,700 |
0.08% |
|
Commercial Total |
56,108,043 |
56.42% |
|
Residential – Multi-family |
17,399,301 |
17.49% |
|
Residential – SFR/Townhomes/Condos |
3,192,262 |
3.21% |
|
Residential Total |
20,591,563 |
20.70% |
|
Mixed-Use – Res & Office |
9,461,808 |
9.51% |
|
Mixed-Use – Res & Retail |
3,714,137 |
3.73% |
|
Mixed-Use – Office & Retail |
2,042,000 |
2.05% |
|
Mixed-Use – Res, Office & Retail |
540,000 |
0.54% |
|
Mixed-Use Total |
15,757,945 |
15.84% |
|
Master Planned Community |
7,000,000 |
7.04% |
|
Grand Total |
99,457,551 |
100.00% |
Top 5 Cities for Major New Commercial Development
The following cities have the greatest amount of major development, consisting of projects in various stages - in review, approved, or under construction, that are at least 80,000 square feet:
- South San Francisco – 22.23 million sq. ft.
- Redwood City – 21.02 million sq. ft.
- Menlo Park – 13.68 million sq. ft.
- Brisbane – 8.27 million sq. ft.
- Burlingame – 6.50 million sq. ft.
"Growth in the technology and life science sectors continues to fuel demand for office, housing, lodging, and retail development," noted Church.
Completed Commercial Projects in 2024
Key completions include the Gateway @ Millbrae Station mixed-use project (161 North Rollins Rd, Millbrae), a life sciences facility at 494 Forbes Blvd in South San Francisco, and Burlingame Park Square (220 Park Road, Burlingame). In total, approximately 1.3 million square feet of commercial space were completed.
Completed Residential Projects in 2024
Notable residential completions included The Overlook (1 Martin Street, Daly City), 815 Old County Road Apartments (Belmont), and two Menlo Park projects, Vasara Apartments (104 Constitution) and Lume Apartments (141 Jefferson). Approximately two million square feet of residential space was completed in 2024.
Sales, Median Prices, and Market Activity
In 2024, San Mateo County’s residential real estate market demonstrated modest but notable growth, despite ongoing macroeconomic challenges. According to data reported by the San Mateo County Association of REALTORS® (SAMCAR), the median sales price for single-family homes rose by 8% to $1,950,000, reflecting continued demand amid limited inventory. The total dollar volume of single-family home sales reached $9.07 billion, an increase of $1.03 billion or 12.8% over the previous year’s total of $8.05 billion.
The condominium market also experienced an increase in overall sales activity. Annual sales volume increased by $194.7 million, or 18.9%, rising from $1.03 billion in 2023 to $1.23 billion in 2024. However, the median sales price for condominiums declined slightly by 1.4%, settling at $915,000, indicating greater price sensitivity in this segment of the market.
Unit sales showed improvement across both residential sectors. Single-family home transactions grew by 8.0%, from 3,292 units sold in 2023 to 3,569 units in 2024. Condominium sales posted a larger increase of 16.5%, with 1,164 units sold in 2024 compared to 999 in the prior year.
“Rising interest rates tested the market’s resolve, but buyers adjusted, developers moved forward, and the result is a roll that continued to grow,” Church noted. “The broader economic conditions are significantly influencing seller behavior. Many homeowners who locked in historically low rates are choosing not to sell. This reluctance is limiting inventory, which in turn impacts both the volume and value of sales,” Church explained. “While activity has picked up compared to last year, it remains well below 2021 levels, and tight supply continues to put upward pressure on home prices,” he added.
Proposition 19: Impact on Assessed Values
Approved by California voters in November 2020, Proposition 19 introduced two major changes to property tax law:
- It imposed tighter restrictions on intergenerational transfer exclusions (parent-to-child and grandparent-to-grandchild).
- It expanded the ability for homeowners over age 55 to transfer base year value to a replacement principal residence (effective April 1, 2021).
The 2025–26 Assessment Roll reflects these changes, with 199 base year transfers, of which 43% 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 7,600 properties for potential declines in 2024 (compared to 11,000 in 2023).
Of those, 6,580 properties qualified for a reduction, with 2,941 partially restored, totaling $3.2 billion in relief. Despite this, the number remains well below the historical high of 34,700 properties in decline in 2010.
An additional 984 properties were fully restored, contributing $269 million in value returned to the roll.
Among the 260 commercial properties receiving relief, 43 more qualified in 2024 than in 2023. However, this remains well below the high of 604 commercial declines in 2011. In total, commercial properties accounted for $911 million of the $3.2 billion in relief.
Over 6,500 affected property owners will receive their FY 2025–26 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 2024, 47 Trustee’s Deeds were recorded, similar to the 48 in 2023. Notices of Default increased slightly to 347, up from 321 in 2023. This modest rise, coupled with stable foreclosure numbers, underscores the market’s resilience, especially when compared to the peak of 5,058 defaults in 2009.
“In 2025, mortgage interest rates remained elevated, yet foreclosure filings stayed notably low. This trend affirms the sustained financial strength of local homeowners, supported by robust employment and a resilient regional economy,” stated Church.
UNSECURED ROLL
The Unsecured Roll represents 3.9% of the Property Assessment Roll and includes business and personal property, possessory interests (such as leases on government property), and air transportation-related assets at San Francisco International Airport (SFO).
The Unsecured Roll totaled $13.45 billion, increasing by just $32 million, 0.24%, over the prior fiscal year.
Addenda:
2025-26 Local Combined Roll
2025-26 Local Secured Roll
2025-26 Local Unsecured Roll
2025-26 Residential Decline in Value Summary