ABAG formed a methodology committee to determine how the need for future housing should be distributed among jurisdictions. The Committee included local elected officials and staff representing every county, as well as regional stakeholders to facilitate sharing of diverse perspectives, and met from October 2019 to December 2020. The Plan Bay Area 2050 Blueprint model was chosen as the starting point, or baseline. For technical details and meeting reports (https://abag.ca.gov/our-work/housing/rhna-regional-housing-needs-allocation/housing-methodology-committee ).
With a projected growth of over 441,000 households for the Bay Area by 2030, San Mateo County was assigned 10.8% of the Bay Area RHNA. Currently the County has 9.4 % of the current population, 10% of the jobs and is estimated to have 10% of the future population.
The RHNA for any given city was primarily based on projected number of households. The baseline is adjusted by factors including proximity to jobs, and high resource areas that have excellent access to amenities such as good schools and employment centers.