https://www.siliconvalley.com/2023/06/16/civil-grand-jury-san-mateo-county-cities-adu-affordable-housing/

Affluent cities in San Mateo County are using accessory dwelling units (ADUs) to meet affordable housing targets set by the state, according to a new report by the county’s civil grand jury. Effectively, this allows these cities to avoid constructing multifamily low-income affordable housing units, the report says.

An ADU — sometimes called a granny flat — is a small secondary housing unit that shares the single-family lot of a larger primary residence. A recent change to California’s 1969 Housing Element Law allows communities to count ADUs as affordable housing in their state-mandated plans.