The Legislature finds and declares that second units are a valuable form of housing in California. Second units provide housing for family members, students, the elderly, in-home health care providers, the disabled, and others, at below market prices within existing neighborhoods. Homeowners who create second units benefit from added income, and an increased sense of security.
It is the intent of the Legislature that any second-unit ordinances adopted by local agencies have the effect of providing for the creation of second units and that provisions in these ordinances relating to matters including unit size, parking, fees and other requirements, are not so arbitrary, excessive, or burdensome so as to unreasonably restrict the ability of homeowners to create second units in zones in which they are authorized by local ordinance.
Source:
Section 65852.150, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=GOV§ionNum=65852.150..