Cal. Education Code § 46148

(a) (1) The schoolday for high schools, including high schools operated as charter schools, shall begin no earlier than 8:30 a.m. (2) The schoolday for middle schools, including middle schools operated as charter schools, shall begin no earlier than 8:00 a.m. (b) For purposes of this section, “schoolday” has the same meaning as defined by the school district or charter school for purposes of calculating average daily attendance in order to compute any apportionments of state funding. This section does not prohibit a school district or charter school from offering classes or activities to a limited number of pupils before the start of the schoolday that do not generate average daily attendance for purposes of computing any apportionments of state funding. (c) This section shall be implemented by middle schools and high schools no later than July 1, 2022, or the date on which a school district’s or charter school’s respective collective bargaining agreement that is operative on January 1, 2020, expires, whichever is later. (d) This section shall not apply to rural school districts. (e) The department is encouraged to post on its internet website available research on the impact of sleep deprivation on adolescents and the benefits of a later school start time and examples of successful strategies for managing the change to a later school start time, and to advise school districts and charter schools of this posting. (f) The Legislature encourages school districts, charter schools, and community organizations to inform their communities, including parents, teenagers, educators, athletic coaches, and other stakeholders, about the health, safety, and academic impact of sleep deprivation on middle and high school pupils and the benefits of a later school start time, and to discuss local strategies to successfully implement the later school start time.