July 2, 2024

Contact: Mark Church, Assessor-County Clerk-Recorder & Chief Elections Officer
Alternate: Jim Irizarry, Assistant Assessor-County Clerk-Recorder
Alternate: Terry Flinn, Special Assistant to the Assessor

(Redwood City, CA) San Mateo County Assessor Mark Church announced today that the County’s Property Assessment Roll increased year-over-year by $17.7 billion, or 5.75%, to a record high of over $325.5 billion in assessed value.  

"San Mateo County delivered another year of impressive roll growth in 2023, demonstrating the County’s economic strength and resilience despite the significant challenges in the real estate and financial markets facing the state and nation," said Mark Church, Assessor-County Clerk-Recorder.

“This year’s roll growth reflects the strength and diversity of San Mateo County’s economy and can be attributed to a steady residential demand and significant commercial development, particularly in the life sciences sector,” stated Church. “It also signifies San Mateo County’s role as one of the strongest economic engines of the Bay Area,” added Church.

However, there have been challenges. The Federal Reserve’s sharp rate hikes in 2022 to curb high inflation led to significant increases in mortgage rates, as residential 30-year jumbo mortgage rates increased from 3.2% in 2022 to over 8% by October 2023, dampening affordability and price growth in the residential housing market. Moreover, the cost of development capital also increased affecting businesses and slowing down the commercial development expansion. 

According to Sotheby’s 2023 annual report, both buyers and sellers began to pull back, as both entry-level and trade-up buyers were impacted. Inflation and high interest rates also caused the risk to go up in commercial property investment and in turn raised the expected return-on-investment, impacting both residential and commercial investment properties.

These economic challenges kept the 2024-25 roll growth in check. According to Sotheby’s annual report, the Tech sector trimmed jobs or underwent a hiring freeze in 2023, impacting the size of the labor force as well as employment in the Bay Area. 2023 also saw the highest job cuts in a decade in San Mateo County in the Life Science sector with 2,264 jobs eliminated, according to the Employment Development Department. Consequently, according to the Employment Development Department (EDD), unemployment increased to 3.3% and the size of the labor force dropped slightly by 1.8%, from 449,600 in 2022 to 441,300 in 2023. However, the unemployment rate in San Mateo County was still the lowest among all counties in California as of December 2023, as reported by the EDD.

Despite these economic challenges, San Mateo County’s 2023 Assessment Roll growth remains strong, coming in slightly below the County’s five-year Assessment Roll average of 6.43%. In addition, San Mateo County’s residential sales started its rebound in the second half of 2023, rising sharply in Spring 2024, with both sales volume and median home prices growing at a solid pace.

San Mateo County has the distinction for having the highest median price for single family residences among all counties in the State, according to the San Mateo County Association of Realtors. Additionally, in 2023, U.S. News and World Report ranked San Mateo County as the fourth wealthiest county in the United States and the second wealthiest in California, due to the county’s high median household income. The county's housing affordability index is at 17%, higher than the state average of 15% reported in 2023, which is attributable to its high median income level.

“It is no surprise that not only the affluent home buyers, but people of all income levels and diverse backgrounds, including a significant number of immigrants, call San Mateo County home”, stated Church. This fact was recognized by the non-profit Welcoming America recently which certified San Mateo County as the ‘Most Welcoming’ and the only county in the nation for its policies that “connect and include people of all backgrounds” to “meet their highest civic, social, and economic potential.”

While our diverse economic base contributes to a favorable long-term outlook, the 2023 sales volume for residential properties declined for both single-family residences (SFRs) and condominiums (condos). Sales of SFRs in 2023, according to San Mateo Association of Realtors (SAMCAR), declined by 17.4% to 3,292 units as compared to 3,987 in 2022, and by 39.6% from two years ago as 5,452 units were sold in 2021. Similarly, sales volume for condos declined even more by 30.4% to 999 units from 1,435 units in 2022, and by 48.4% as compared to 1,935 units sold in 2021. 

The median SFR price reached an all-time high of $2.30 million in May 2024, according to SAMCAR. The increase was a significant improvement from the low of $1,652,500 reported in December 2023. The condominium median price rose from a low of $826,500 in December 2023, to a high of $930,000 in May 2024. “While seasonal changes play a part, other factors influencing the sharp increases in median prices include the market’s acceptance of, and adjustment towards, higher mortgage rates, resulting in the sharp increases in inventory, sales volume and prices from December 2023,” stated Church.

Highlights of the 2024 Roll
“The 2024-25 combined Assessment Roll reflects the fourteenth consecutive year in which a new historical high has been achieved,” reported Church.

The 2024-25 Property Assessment Roll reflects overall growth throughout the County. “Total assessed values increased in all 20 cities and unincorporated areas, ranging from 2.39% to as high as 13.93% and an overall increase of 5.75%. The County’s unincorporated areas, which include San Francisco International Airport (SFO), experienced a growth rate of 8.15%,” added Church.

In response to the declines in value of certain properties, the Assessor’s Office again took proactive measures this year and reviewed over 11,000 properties potentially impacted by declining values in 2023, as compared to 10,000 properties that were reviewed for 2022. However, the number of properties in decline remained almost unchanged from the previous year. A total of 6,405 residential properties qualified for the Proposition 8 Decline in Value Program for 2023 as compared to 6,403 for 2022. However, this number remains significantly below the 34,700 properties that suffered a decline for 2010. Similarly, on the commercial side, 25 fewer properties qualified for property tax relief compared to 242 for 2022, a number still substantially below the high of 604 properties for 2011. 

The top 5 cities with the highest percentage growth in Assessed Value are:

  • Brisbane                             13.93%
  • Burlingame                         8.30%
  • Daly City                              7.87%
  • South San Francisco         7.51%
  • Millbrae                               6.89%

 The top 5 cities with the highest dollar growth in Assessed Value are:​

  • South San Francisco         $2.31 billion
  • San Mateo                           $1.76 billion
  • Burlingame                          $1.36 billion
  • Daly City                               $1.27 billion
  • Redwood City                     $1.06 billion

The assessed value increases in these five (5) cities total over 43.84% of the 2024-25 Roll increase.

The shared property tax funding base is approximately 1% of the County’s Property Assessment Roll increasing to $3.25 billion. Approximately 52% of revenue is allocated to schools within the county, 25% to the County, 15% to cities, 7% to special districts, and 1% to former redevelopment agencies. “The County’s share will be 25%, or approximately $813.7 million, an increase of $44.3 million over last year,” noted Church. 

The Property Assessment Roll is the assessed value of all properties as of January 1 each year and reflects changes in ownership, new construction, value declines, and value restorations from the previous January 1. The Property Assessment Roll is composed of two sections, the Secured and Unsecured Rolls. When combined, the two sections are referred to as the Combined Roll.

The Secured Roll represents 95.9% of the Combined Roll and includes 222,591 commercial, residential, and agricultural real properties. This year, the Secured Roll increased to $312.0 billion, an increase of $16.7 billion or 5.66% over 2023-24, reflecting continued economic growth in the County.  

The growth of the San Mateo County Secured Roll is primarily due to the following factors:

New Commercial Development. Exceeding the previous year in terms of growth, large commercial, residential, and mixed-use construction projects were among the major contributors to 2024-25 Roll growth. Major projects in the County, consisting of 80,000 square feet or more, accounted for more than 3.8 million square feet of completed new development coming to market in 2023, compared to 2.75 million square feet completed in 2022.

Overall, 12 to 13 million square feet of new construction is expected to be completed in the County over the next five years, including an estimated 3 million square feet in 2024. There are 13.6 million square feet under construction, 14.2 million square feet have planning approval, and 43.8 million square feet are under review. Approximately 28.4 million square feet of major new construction have been completed since 2015.

Commercial projects account for 56.51% of all major construction projects tracked by the Assessor’s office, followed by 21.04% residential and 15.42% mixed-use projects. The following table shows the percentages attributed to each major use type in the county’s development pipeline.

New Major Development (Tracked since 2015)

Property Category

Development Size (Sq. Ft.)


Life Science









Senior Care Facility



Industrial Park















Residential - Multi-family



Residential - SFR / Townhouse / Condos









Mixed-Use Residential & Office



Mixed-Use Residential & Retail



Mixed-Use Office & Retail



Mixed-Use Residential, Office & Retail






Master Planned Community



Grand Total



Commercial Sq. Ft. 56,232,400 56.51%
Residential Sq. Ft. 20,939,305 21.04%
Mixed-Use Sq. Ft. 15,346,427 15.42%
Master Planned Community Sq. Ft. 7,000,000 7.03%
Grand Total 99,518,132 100.00%

Top 5 Cities for New Commercial Development. The following cities have the greatest amount of major development, consisting of projects that are 80,000 square feet or more that are pending, approved, or under construction:

  • South San Francisco - 22.47 million square feet
  • Redwood City - 22.17 million square feet
  • Menlo Park - 12.17 million square feet
  • Brisbane - 8.27 million square feet
  • Burlingame - 6.53 million square feet

“Growth in the Technology and Life Science sectors continues to drive the demand in office, housing, lodging, and retail,” noted Church.

Completed commercial projects in 2023 includes South San Francisco Civic Center at 400 Grand Ave, YouTube office building at Bay Hill, San Bruno. Hotels at 2940 South Norfolk Street, San Mateo, and 301-309 Constitution Drive, Menlo Park, were also completed during the year. Life Science was led by the completion of Life Science buildings at 348-354 Oyster Point Blvd and 700- 900 Gateway Blvd in South San Francisco; followed by Sierra Point Pkwy at Shoreline Ct and 3000-3500 Marina Blvd in Brisbane. Approximately 3.3 million square feet of commercial development were completed in 2023.

Residential completions were led by 353 Main Street in Redwood City; 1095 Rollins Road in Burlingame, Skyline College Residential in San Bruno, and Jefferson Union High School District Faculty and Staff Housing in Daly City. Over half a million square feet of residential development were completed in these projects.

Sales and Ownership Changes. Sales and changes in ownership totaled $12.5 billion, or about 75% of this year’s Secured Roll increase of $16.7 billion. Residential sales accounted for about 93% of that dollar growth, while commercial sales accounted for 7%.

Sales, Median Prices, and Market Activity. The San Mateo County Association of Realtors (SAMCAR) reported, median sales prices of single-family homes in San Mateo County increased by 7% in December 2023 to $1,652,00 as compared to $1,545,000 in December 2022. The total dollar value of sales increased by 18.3% for single-family homes to $573.6 million. The condominium sales volume in dollars increased at a relatively low pace at 7% for the same period, while the median price remained almost unchanged at $826,500. The number of sales increased modestly by 4.13% for single-family homes from 242 to 252, and 8.47% for condominiums, from 59 to 64 in December 2023, compared to a year ago. “This variance appears to indicate buyers’ willingness to accept both the high mortgage rates and the higher price of single-family homes, once again confirming the presence of relatively high concentration of affluent buyers in the County,” Church stated.

Prop 19: Impact on Assessed Values. In November 2020, California voters approved Proposition 19, which made two significant changes in California property tax law.

1) The new law created more restrictions to using intergenerational transfers that qualify for exclusion from reassessment between parents and their children and between grandparents and grandchildren. Intergenerational transfers are now restricted to a property that the transferee child or grandchild designates as their principal residence; and

2) Prop 19 changed the criteria for property owners over 55 years old who wished to transfer the assessed value from one principal residence to a replacement principal residence. This provision took effect on April 1, 2021. It allows a transfer of a lower property tax base from any county in California up to three times. If a property owner purchases a more expensive replacement principal residence, any amount above the qualified value of the original residence is added to the transferred value.

The impact of these new regulations on assessed values is now reflected in our 2024 Assessment Roll. The 2024 Assessment Roll included 135 base year transfers, of which 41% were transfers from outside San Mateo County.

Reduction in Assessed Value: Proposition 8/Decline in Value Program. The Proposition 8/Decline in Value Program provides property tax relief to property owners when the market value of a property falls below its assessed value. As noted previously, a review of over 3,800 properties was completed that could have been affected by the declining values in 2023. A total of over 11,000 properties were reviewed, including over 6,000 that were reviewed last year. However, the total residential properties qualifying for the Proposition 8 Decline in Value Program remained almost unchanged at 6,405 in 2024-2025, compared to 6,403 in 2023-2024. Similarly, on the commercial side, 25 fewer properties qualified for property tax relief compared to 242 in 2023-24.

Over the next few days, more than 6,000 residential property owners enrolled in the program will be mailed their 2024-25 Assessed Value Notices. Among them are 1,274 properties that have recovered in value for various reasons and are now being fully restored to their factored base-year (Prop 13) values.

Annual Inflation Factor. Proposition 13, which governs property taxation in California, ties the annual inflation factor to the California Consumer Price Index (CCPI) issued by the California Industrial Relations Board and limits annual inflation increases to no more than 2%. This year an annual inflation factor of 2% was applied to the assessed value of all real property that did not have a change in ownership or any new construction during 2023.

Recorded Foreclosures. There were 48 Trustee’s Deeds recorded in the calendar year 2023, which is 22 more than the 26 recorded in 2022. Notices of Default have increased to 321 in 2023, 28 more than 293 recorded in 2022. As forecasted last year, the decline suffered by many properties purchased at the peak of the market and high mortgage rates for those with adjustable rates have resulted in a higher rate of foreclosures this year. However, the total number of default notices is still relatively small compared to the high in 2009 when 5,058 were recorded.

“Although mortgage interest rates remained high in 2023, recorded foreclosures are still low, indicating financial resilience of local residential real estate equity, continued high employment levels and the strength of the local economy,” stated Church.

The Unsecured Roll comprises approximately 4.1% of the Property Assessment Roll and includes the valuations of business/personal property, air transportation-related property at SFO, and possessory interests (government property leased by businesses). This year, the Unsecured Roll increased to $13.42 billion in assessed value, an increase of almost $1 billion or 8.03% over the prior year’s Unsecured Roll. 

This year’s increase is primarily due to increased assessment of taxable Possessory Interests at San Francisco International Airport and commercial airlines. The increase is also driven by both the expansion of existing businesses and the establishment of new businesses within San Mateo County. 


2024-25 Local Combined Roll
2024-25 Local Secured Roll
2024-25 Local Unsecured Roll
2024-25 Residential Decline in Value Summary

Related Contacts

Mark Church

Assessor-County Clerk-Recorder and Chief Elections Officer
555 County Center
Redwood City, CA 94063-1665Get Directions

Jim Irizarry

Asst. Assessor-County Clerk-Recorder & Asst. Chief Elections Officer
555 County Center
Redwood City, CA 94063-1665Get Directions

Terry Flinn

Special Assistant to the Assessor