California Code, Government Code - GOV § 65850.02

(a) Notwithstanding any other local law, with respect to land zoned for residential use, the legislative body of a city or county shall not adopt or enforce an ordinance requiring a public hearing as a condition of reconfiguring existing space to increase the bedroom count within an existing dwelling unit.

(b) This section shall only apply to a permit application for no more than two additional bedrooms within an existing dwelling unit.

(c) This section shall not be construed to prohibit a local agency from requiring a public hearing for a proposed project that would increase the number of dwelling units within an existing structure.

(d) The Legislature finds and declares that ensuring adequate housing is a matter of statewide concern and is not a municipal affair, as that term is used in Section 5 of Article IX of the California Constitution. Therefore, this section applies to all cities, including charter cities.