Average Units per Acre of Newly Approved Residential Development
City Planning and Housing Departments of Silicon Valley
Silicon Valley Institute for Regional Studies
Data are from Joint Venture Silicon Valley’s annual land-use survey of all cities within Silicon Valley. The 34 cities/counties included in the FY 2021-22 Residential Density analysis are Belmont, Burlingame, Campbell, Brisbane, Colma, Cupertino, East Palo Alto, Fremont, Gilroy, Half Moon Bay, Hillsborough, Los Altos, Los Altos Hills, Los Gatos, Menlo Park, Millbrae, Milpitas, Monte Sereno, Morgan Hill, Mountain View, Newark, Pacifica, Redwood City, San Bruno, San Carlos, San Jose, San Mateo, San Mateo County, Santa Clara, Saratoga, South San Francisco, Sunnyvale, Union City, and Woodside; ADU count for 2021-22 also includes Palo Alto, Daly City, Foster City, and the County of Santa Clara. Other cities/counties were not included because they either did not respond to the survey or they left the acreage question blank. Most recent data are for fiscal year 2022 (July 2021 through June 2022). Residential density was calculated as the average residential density of the participating cities/counties for each year. Beginning with FY 2014-15 the residential density calculation included accessory dwelling units (ADUs), and starting in 2018-29 they also included ADUs that were issued a building permit in lieu of a planning approval.
Beginning in 2008, the Land Use Survey was expanded to include cities northward along the U.S. 101 corridor (Brisbane, Burlingame, Millbrae, San Bruno and South San Francisco). In 2014, the Survey was further expanded to include all Silicon Valley cities (adding Colma, Daly City, Half Moon Bay and Pacifica). Beginning in 2020, the residential density calculation included accessory dwelling units (ADUs) that were issued a building permit in lieu of a planning approval.