San Mateo County, CA median household income trends: 2010 to 2021
From 2010 to 2021, the median household income for San Mateo County increased by $32,346 (27.99%), as per the American Community Survey estimates. In comparison, median household income for the United States increased by $4,559 (6.51%) between 2010 and 2021.
Analyzing the trend in median household income between the years 2010 and 2021, spanning 11 annual cycles, we observed that median household income, when adjusted for 2022 inflation using the Consumer Price Index retroactive series (R-CPI-U-RS), experienced growth year by year for 8 years and declined for 3 years.
The most significant year-by-year growth occured from 2018 to 2019, when the median household income increased by 7,807 (from $133,011 to $140,818). Similarly the most substantial year-by-year decline occured from 2011 to 2012, when the median household income decreased by 2,196 (from $114,587 to $112,391).
When compared to all of the counties in the state of California, San Mateo County is ranked 2nd among the 58 counties for its median household income. This ranking suggests that San Mateo County is among the top-performing counties in California, in terms of median household income.
Median household income in San Mateo County, CA by household size
To gain deeper insights into the median household income for San Mateo County, we conducted an analysis of the most recent available data from the U.S. Census Bureau American Community Survey 5 year Estimates (the most recent data available).
Of the 7 household sizes (1 person to 7-or-more person households) reported by the census bureau, all of the household sizes were found in San Mateo County. Across the different household sizes in San Mateo County the mean income is $175,684, and the standard deviation is $49,883. The coefficient of variation (CV) is 28.39%. This high CV indicates high relative variability, suggesting that the incomes vary significantly across different sizes of households.
In the most recent year, 2021, The smallest household size for which the bureau reported a median household income was 1-person households, with an income of $73,142. It then further increased to $193,476 for 7-person households, the largest household size for which the bureau reported a median household income.
San Mateo County median household income by household size
The table below displays median household incomes for various household sizes, as reported by the U.S. Census Bureau. Explore how household income varies with the size of the family unit.
| Household Size | Median Household Income |
|---|---|
| 1-person households | 73,142 |
| 2-person households | 158,154 |
| 3-person households | 181,280 |
| 4-person households | 228,405 |
| 5-person households | 200,316 |
| 6-person households | 195,016 |
| 7-or-more-person households | 193,476 |
According to the Census Bureau data, the median household income reaches its peak among 4-person households, reaching $228,405 .
San Mateo County, CA income distribution and inequality
To gain a comprehensive understanding of income distribution in San Mateo County, we conducted an analysis of quintiles data from the U.S. Census Bureau. While the bureau does not categorize income into subjective classes like lower-income, middle-class, or upper-class, they instead divide the population into five quintiles, ensuring that each quintile represents nearly the same number of households. This classification allows us to analyze income levels across a spectrum from the lowest to the highest income groups.
Mean household income by quintile in San Mateo County
The table below presents the mean household income for each of the five quintiles in San Mateo County, offering valuable insights into income distribution and inequality.
| Income Level | Mean Household Income |
|---|---|
| Lowest Quintile | 29,711 |
| Second Quintile | 84,491 |
| Third Quintile | 147,273 |
| Fourth Quintile | 238,587 |
| Highest Quintile | 583,538 |
| Top 5 Percent | 1,050,578 |
Key findings:
- Income disparities: The mean income of the lowest quintile (20% of households with the lowest income) is 29,711, while the mean income for the highest quintile (20% of households with the highest income) is 583,538. This indicates that the top earners earn 20 times compared to the lowest earners.
- Top 5%: The mean household income for the wealthiest population (top 5%) is 1,050,578, which is 180.04% higher compared to the highest quintile, and 3535.99% higher compared to the lowest quintile.
Furthermore, as per the Census Bureau, the Gini coefficient for San Mateo County is 0.5041. Gini coefficient is a numeric measure ranging from 0 to 1, where lower numbers indicate greater income equality (with 0 representing complete equality, where all households earn the same income) and higher values signify greater income inequality (with 1 being complete inequality where one household receives all income).
Sources: U.S. Census Bureau, American Community Survey (ACS)
With a Gini coefficient of 0.5041, it is evident that income distribution in San Mateo County, CA exihibits characterstics of moderate inequality .
This level of Gini coefficient suggests noticeable variations in income distribution across households, with certain segments of the population holding a larger share of income compared to others in San Mateo County.
It also implies that efforts may be needed to enhance economic fairness and reduce the gap between income groups in San Mateo County