Here’s the average size of a family living together in the Bay Area by county, according to the latest update of census data.1. Santa Clara — 3.43 people2. San Mateo — 3.393. Alameda — 3.363. Solano — 3.365. Contra Costa — 3.346. Napa — 3.297. San Francisco — 3.148. Marin — 3.029. Sonoma — 2.59Other than Sonoma County, all of these numbers are well above the national rate of 2.64 family members per household. The numbers have also risen over time; in 2010, Santa Clara was at 2.86 and San Mateo at 2.72.
Adult children are moving back home after college often because rents are rising faster than fixed incomes can bear. Is that having an effect on the average size of a Bay Area family household?