Since the 1st-quarter of 2022, San Bruno house price appreciation has not kept up with San Mateo County. Similar low appreciation is seen for other cities near San Francisco.
San Bruno House Prices vs. San Mateo County House Prices

The upper traces show San Mateo County house prices. The lower traces show San Bruno house prices. In the early 2000’s, the government supported relaxed loan qualifications for low-income home buyers to help more people become homeowners. It is not surprising that the 2008 mortgage crisis affected lower-priced homes in San Bruno more than the San Mateo County average and median. What is interesting is that after the 1st-quarter of 2022 San Bruno prices appreciated less than San Mateo County prices.
San Bruno House Age vs. San Mateo County House Age
New homes sell at a premium compared to older homes. Consider how the age of the typical houses sold would affect prices.

The faint red line shows the average age of houses sold in San Mateo County. The strong red line shows the average age of San Bruno houses sold. With an older average age after the 2nd quarter of 2019, it could be expected that San Bruno house prices would not keep up with San Mateo County.
Generally, multiple factors affect house price appreciation. The age of houses sold appears to be a factor for lower price appreciation in San Bruno vs. San Mateo County. More information about these real estate trends is available at https://julianalee.com/blog/san-mateo-county-vs-santa-clara-county-real-estate-trends-age/ .